Initial Snohomish River Basin Chinook Salmon Conservation/Recovery Technical Work Plan
Snohomish Basin Salmonid Recovery Technical Committee
October 6, 1999
Initial Snohomish River Basin Chinook Salmon Table of Contents Conservation/Recovery Technical Work Plan
TABLE OF CONTENTS
LIST OF TABLES ...... IV
LIST OF FIGURES ...... IV
EXECUTIVE SUMMARY...... V A. INTRODUCTION...... v B. SNOHOMISH BASIN OVERVIEW...... v C. PROCESSES THAT FORM AND MAINTAIN HABITAT...... v D. STATUS OF THE POPULATION...... vi E. FACTORS AFFECTING THE POPULATION...... vii F. ACTIONS...... xi G. NEXT STEPS...... xiii I. INTRODUCTION...... 1 A. PLAN FOCUS AND PHILOSOPHY ...... 1 B. ENDANGERED SPECIES ACT LISTING ...... 2 C. GENERAL BASIN CONDITIONS ...... 2 D. TECHNICAL WORK PLAN PROCESS...... 4 E. STATE AND REGIONAL EFFORTS ...... 5 II. CHINOOK SALMON HABITAT REQUIREMENTS ...... 7 A. LIFE HISTORY PATTERNS...... 7 B. FRESHWATER HABITAT REQUIREMENTS...... 7 C. ESTUARY HABITAT REQUIREMENTS ...... 10 D. SUMMARY ...... 11 III. PROCESSES THAT FORM AND MAINTAIN HABITAT...... 13 A. INTRODUCTION...... 13 B. NATURAL PROCESSES THAT SHAPED PUGET SOUND RIVERS AND SALMON POPULATIONS 13 C. THE RIVER CONTINUUM...... 14 1. Longitudinal ...... 14 2. Latitudinal (Horizontal)...... 15 3. Vertical...... 16 4. Temporal ...... 16 D. FLOODPLAIN HABITAT FORMATION AND USE...... 16 E. SUMMARY: NATURAL HABITAT DIVERSITY AND DYNAMISM...... 20 IV. STATUS OF THE POPULATION...... 21 A. SPECIES COVERED...... 21 B. POPULATION SIZE...... 22 C. DELINEATION AND CHARACTERISTICS OF STOCKS...... 23 1. Snohomish River Summer...... 24 2. Snohomish River Fall...... 25
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3. Bridal Veil Creek Fall...... 26 4. Wallace River Summer/Fall ...... 27 5. Possibility of Spring Stock ...... 27 V. FACTORS AFFECTING THE POPULATION ...... 29 A. HARVEST, HATCHERIES, HYDROPOWER AND HABITAT...... 29 B. HARVEST...... 29 C. ARTIFICIAL PRODUCTION ...... 31 1. Wallace River Hatchery ...... 34 2. Tulalip Hatchery ...... 37 D. HYDROPOWER PROJECTS...... 38 1. Henry M. Jackson Hydroelectric Project...... 39 2. South Fork Tolt River Hydroelectric Project...... 39 3. Other Projects ...... 41 E. FRESHWATER AND ESTUARINE HABITAT...... 41 1. Human Populations and Land Use ...... 42 2. Interaction of Human Populations, Land Use and Habitat Conditions...... 46 3. Factors Contributing to Decline ...... 52 4. Remaining Critical Habitat and Linkages ...... 54 F. MARINE SURVIVAL...... 58 1. Ocean Conditions...... 58 2. Salmon as Prey and Predator ...... 59 G. NON-NATIVE SPECIES ...... 60 H. DATA GAPS ...... 61 1. Basin-Wide ...... 61 2. Snohomish River Estuary ...... 64 3. Snohomish River Mainstem...... 65 4. Skykomish River Mainstem...... 65 5. Skykomish River Forks ...... 66 6. Snoqualmie River ...... 66 VI. ACTIONS...... 67 A. INTRODUCTION...... 67 B. HARVEST MANAGEMENT PLAN ...... 67 1. Goal and General Principles ...... 68 2. Interim Harvest Management Plan ...... 68 3. Development of Long-Term Harvest Management Plan...... 71 C. ARTIFICIAL PRODUCTION MANAGEMENT PLAN...... 71 1. Background ...... 71 2. Categories of Artificial Production...... 72 3. Program Descriptions...... 73 4. Actions...... 76 D. HABITAT MANAGEMENT PLAN...... 76 1. Principles Underlying Work Plan ...... 76 2. Categories of Action...... 79 3. Time Scale for Expected Results ...... 80
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4. Known/Suspected Problems ...... 80 5. List of Problems and Actions ...... 81 E. MULTI-JURISDICTIONAL PROGRAMMATIC ASSESSMENT...... 91 F. NON-NATIVE SPECIES MANAGEMENT PLAN...... 92 G. ADAPTIVE MANAGEMENT STRATEGY AND ACTIONS ...... 92 1. Elements of Effective Adaptive Management ...... 93 2. Application of Adaptive Management in the Snohomish River Basin Response...... 94 3. Understanding the limits of Adaptive Management...... 95 VII. NEXT STEPS ...... 97 A. PRESENT TO FORUM ...... 97 B. INTEGRATE POLICY CONSIDERATIONS INTO PLAN ...... 97 C. LAUNCH EARLY ACTIONS ...... 97 D. DEVELOP MORE GEOGRAPHIC SPECIFICITY...... 97 E. DEVELOP RESEARCH PROGRAM ...... 98 F. CREATE FRAMEWORK FOR MULTI-SPECIES PLAN...... 98 REFERENCES...... 99
APPENDIX A: CONTRIBUTING AUTHORS AND COMMITTEE MEMBERS ...... 111
APPENDIX B: PROBLEM STATEMENTS...... 113
APPENDIX C: TECHNICAL EVALUATION OF THE NINE HIGHEST PRIORITY PROBLEM STATEMENTS ...... 115
APPENDIX D: MARINE MAMMAL PREDATION ON SALMONIDS...... 117
APPENDIX E: EARLY ACTION PROJECTS SUBMITTED FOR STATE FUNDING UNDER 75.46 RCW...... 118
APPENDIX F: GLOSSARY...... 123
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LIST OF TABLES
Table 1. Summary of remaining critical habitat and linkages...... x Table 2. Summary of recommended protection actions for priority habitat problems...... xii Table 3. Estimated natural spawning escapement of chinook salmon by stock...... 22 Table 4. Wallace River hatchery releases of chinook salmon in the Snohomish River basin...... 36 Table 5. Tulalip Hatchery releases of chinook salmon into Tulalip Bay...... 37 Table 6. Current Snohomish River basin chinook salmon releases...... 75
LIST OF FIGURES
Figure 1. Location of Snohomish River basin...... v Figure 2. Summary of chinook salmon escapement in the Snohomish River basin ...... vi Figure 3. Sub-basins of the Snohomish River basin...... viii Figure 4. Map of Snohomish River watershed with sub-basin boundaries ...... 3 Figure 5. Approximate extent of known current chinook salmon habitat...... 21 Figure 6. Estimated natural spawning escapement of chinook salmon by stock...... 23 Figure 7. Major chinook salmon artificial production facilities ...... 34 Figure 8. Major dams and hydropower projects in the Snohomish River watershed...... 40 Figure 9. Land use in the Snohomish River watershed...... 43
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EXECUTIVE SUMMARY
A. INTRODUCTION The purpose of this document is to provide a technical basis for a chinook salmon conservation and recovery plan for the Snohomish River basin (Water Resource Inventory Area 7). While it is not a comprehensive recovery plan, it is intended to contribute to chinook salmon recovery in the short term and provide a starting point for a longer-term, multi-species salmonid recovery plan.
The Snohomish Basin Salmonid Recovery Technical Committee is composed of approximately thirty representatives of governmental and non-governmental organizations (Appendix A). Members have technical expertise and interest in the conservation and recovery of salmon populations in the Snohomish River watershed. The Technical Committee adopted five principles to guide its efforts in the development of this initial work plan:
1. Emphasize protection and reconnection of habitat; 2. Use historical information to guide today’s decisions; 3. Preserve and restore the natural ecosystem processes; 4. Use monitoring and assessment to guide adaptive management; and 5. Preserve options for the future.
B. SNOHOMISH BASIN OVERVIEW At 1,856 square miles in area, the Snohomish River basin is the second largest watershed draining to Puget Sound (Figure 1). It includes the Skykomish, Snoqualmie, and Snohomish rivers, along with numerous tributaries. This ecosystem supports significant populations of native salmonids including coho, chinook, chum and pink salmon; steelhead, rainbow, cutthroat and bull trout; and mountain whitefish.
In May 1999, the National Marine Fisheries Service Figure 1. Location of Snohomish (NMFS) listed the Puget Sound chinook salmon stocks River basin. as threatened under the Endangered Species Act (ESA). This listing includes the stocks native to the Snohomish River basin.
C. PROCESSES THAT FORM AND MAINTAIN HABITAT Salmon in the Pacific Northwest have evolved through complex interactions with their freshwater, estuarine, and marine environments. These environments are created and maintained by physical, chemical and biological processes acting over a range of spatial and temporal scales. Though salmon have existed for several million years, conditions in the Snohomish River basin were largely reset 6 – 8,000 years ago following the most recent glacial period. Since that time the major processes forming and maintaining habitat have included:
v Initial Snohomish River Basin Chinook Salmon Executive Summary Conservation/Recovery Technical Work Plan
• Precipitation in the form of snow and rain creating conditions for runoff; • Redistribution and sorting of sediment based on energy gradients and sources; • Migration of channels across their floodplains creating habitat with a diversity of flow conditions, food supplies, cover, and substrate conditions; • Vegetative growth of long-lived species that play a dominant role in modifying local energy gradients and sediment dynamics; and • The development of a plethora of biological niches at all scales.
The environment includes disturbance, even in the pre-development situation, by geologic mass movement, fire, flooding and disease outbreaks. Over the spatial scale of the basin and the temporal scale of several thousand years, such disturbances are local and short-lived. The resulting natural environment is locally diverse, yet regionally predictable.
Large-scale disruption and acceleration of these processes has occurred since the 1850s. Human activities have fundamentally changed the way water, wood and sediment move through the watershed. Hydromodifications (dikes, levees, revetments, etc.) have further affected sediment dynamics, flood frequency and levels, and nutrient dynamics. These changes have affected the life cycles of salmon in the Snohomish River basin.
D. STATUS OF THE POPULATION
This report focuses on chinook salmon (Oncorhynchus 10,000 tshawytscha) populations that spawn and rear in the System Total Snohomish River basin. In the absence of biologically 8,000 12-Year Average determined productivity goals, fishery biologists use 6,000 the average annual escapement from 1965 – 1976 as a target escapement level. For the Snohomish River 4,000
basin, the target is 5,250 fish returning each year. For Number of Fish 2,000 comparison, the most recent available 12-year average was 4,013 fish from 1987 – 1998 (Figure 2). 0 1965 1969 1973 1977 1981 1985 1989 1993 1997 Naturally spawning chinook salmon in the Snohomish Year River basin are divided into four stocks. The division Figure 2. Summary of chinook is based on differences in spawning timing, salmon escapement in the Snohomish geographical spawning distribution and genetic River basin, 1965 – 1998. characteristics.
• Snohomish River Summer. The escapement of this stock has been declining, and 1997 had the lowest escapement ever recorded. The proximity of the Wallace River hatchery may lead to significant straying of hatchery fish into the spawning area. • Snohomish River Fall. In contrast to the general downward trend for chinook salmon escapement in the basin, the escapement for this stock has been increasing. • Bridal Veil Creek Fall. Escapement has dropped substantially since the mid-1970s. • Wallace River Summer/Fall. The Wallace River stock is considered to be a mixture of stocks resulting from hatchery straying and natural production. This stock was considered healthy in 1993, but recent escapements have been down from the 1965-1976 base year period.
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E. FACTORS AFFECTING THE POPULATION
1. Marine Survival Ocean conditions are cyclic, and the ocean’s carrying capacity for salmonids is dynamic in time and space. Salmon populations naturally exhibit highly variable abundance. Currently, Puget Sound stocks generally appear to be experiencing a period of lower than average marine survival.
While predation is a factor, it is part of the natural ecosystem in which salmon evolved. In the North Pacific Ocean, approximately fifteen species of marine mammals reportedly eat salmon. Although salmon are not their primary prey, seal and sea lion predation can have significant impacts on salmon populations when those populations are already depressed by other factors.
2. Harvest Chinook salmon from Puget Sound are harvested throughout much of their marine residency in ceremonial, subsistence, commercial, and recreational fisheries from Alaska to Puget Sound. In most cases, fishing mortality on Snohomish River chinook salmon is incidental to fisheries targeting other stocks or species. Estimated exploitation rates on the Snohomish River chinook salmon management unit declined steadily from approximately 80% in the late 1970s to approximately 55% in the mid-1990s. The rates have likely declined further in the late 1990s, to as low as 35%, because of increased restrictions on fishing.
3. Artificial Production Chinook salmon have been produced and released into the Snohomish River basin for the past century. This production poses potential risk to wild populations in the basin in three ways:
• Introgression of genes from hatchery populations into wild populations; • Adverse effects from competition, predation and other ecological factors; and • Masking the true status of wild fish due to large numbers of hatchery fish.
The State and Tribal co-managers are examining and evaluating these risk factors through intensive marking and monitoring of hatchery production at the Wallace River and Tulalip hatcheries and modification of hatchery programs where appropriate. The Snohomish River system is managed primarily for wild production and only secondarily for hatchery production of all species of salmonids. Currently, fisheries targeted at hatchery production occur only where hatchery fish can be separated in space and time from wild fish, as in Tulalip Bay, or through visible mass marking of hatchery fish and implementation of selective retention regulations.
4. Hydropower Unnatural fluctuations in stream flow occur downstream of hydroelectric facilities, based on how the facility is designed and operated. Water level fluctuations associated with hydropower operations may reduce habitat availability, de-water spawning areas, restrict access or strand fish, or affect the migratory behavior of juvenile salmonids. Instream flow schedules, minimum flow requirements, and down-ramping prescriptions are operational means of protecting the aquatic
vii Initial Snohomish River Basin Chinook Salmon Executive Summary Conservation/Recovery Technical Work Plan resources downstream of hydroelectric facilities. Hydroelectric dams may also modify sediment and woody debris transport, water temperatures and the concentration of dissolved gasses.
Two types of hydroelectric operations are present in the Snohomish River basin: storage facilities and run-of-the-river facilities. The Henry M. Jackson and the South Fork Tolt River hydroelectric projects are both storage facilities. The remaining projects in the basin are run-of- the-river operations with little or no storage, and they are all upstream of natural barriers to anadromous fish migration.
5. Freshwater and Estuarine Habitat a) Human Populations and Land Use
Important human land uses in the basin include forestry, urban, residential, light industrial, infrastructure (roads and railroads; gas, water and power lines), recreation, agriculture and mining. The Snohomish River basin is a major source of municipal water supply for Everett, Seattle, southwest Snohomish County and other areas. Human population in the basin is projected to increase by 53% from 206,000 in 1995 to 315,000 in 2020. Types of land use, population densities and likely impacts on chinook salmon habitat vary greatly across the watershed, so they are considered separately for the following five sub-basins (Figure 3).
• Snohomish River Estuary and Nearshore Areas. This 154 square mile area is the most heavily urbanized portion of the Snohomish River basin. Major land uses include urban, residential, agriculture, transportation and commercial/industrial. The natural conditions have been heavily modified throughout this sub-basin.
• Snohomish River Mainstem. This 178 square mile sub-basin includes the Pilchuck River and tributaries that empty into the Snohomish River below the confluence of the Snoqualmie and Skykomish rivers. The majority of the land is designated for rural residential uses, and approximately 20% of the basin is forested. Agricultural use Figure 3. Sub-basins of the Snohomish occupies the floodplain. River basin.
• Skykomish River Mainstem. The Skykomish River mainstem and its tributaries (below the confluence of two major forks near Index) drain 325 square miles, more than three-quarters of which are forested hills and mountains. The most common land use outside the forests is residential, with extensive agriculture in the floodplain.
viii Initial Snohomish River Basin Chinook Salmon Executive Summary Conservation/Recovery Technical Work Plan
• Skykomish River Forks. This sub-basin drains 507 square miles, 98% of which are forested. Low density residential development along the valley floors makes up most of the rest of the land use.
• Snoqualmie River. The Snoqualmie River watershed comprises 692 square miles. Predominant land uses are forestry, covering 75% of the area, agriculture and residential. There is potential for high-density development in some areas. b) Interaction of Human Populations, Land Use and Habitat Conditions
Over the past 150 years, human activities have altered the habitat used by salmon and disrupted the natural processes that maintain it, although some areas still support natural functions. Physical changes that affect chinook salmon habitat have included loss of wetlands; placement of roads, railroads, levees, and revetments in areas that cut off side channel habitat or limit the natural process of channel migration; bank stabilization; diking; dredging; gravel mining in the floodplain; development and filling of the floodplain; clearing and road-building on unstable slopes; removal of trees and large woody debris; log rafting; water withdrawals; and construction of fish passage barriers and impervious surfaces. These changes alter the hydrology, channel morphology, sediment transport and other processes that maintain salmon habitat.
For example, rip-rapping, diking and dredging confine river channels to their present courses to prevent channel flows from reaching the floodplain. This interferes with the natural process of recruiting large woody debris and depositing sediment across the floodplain. Dredging can also lower the water table, which in turn affects stream temperatures and water flows. c) Factors Contributing to Decline
The Technical Committee examined freshwater and estuarine habitat conditions in the basin and considered how they may limit the productivity of salmon in four ways:
• Loss of rearing habitat quality and quantity; • Decreased egg to emergent survival; • Acute juvenile mortality; and • Adult mortality.
The Technical Committee identified several problems that contribute to the degradation of habitat and the subsequent decline in chinook salmon productivity. They evaluated each of these problems and identified nine which are the highest priority for salmon recovery in the basin:
1. Loss of channel area and complexity due to bank protection and diking of the river and major tributaries, cutting off the channel from its floodplain; 2. Dearth of in-channel large woody debris; 3. Flood flows that scour redds at high frequencies; 4. Increased sediment input to streams as a result of slope failures; 5. Poor quality riparian forests;
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6. Loss of wetlands due to draining for land conversion that eliminates habitat and reduces water retention; 7. In redd mortality due to siltation or water quality contamination; 8. Urbanization (road construction, commercial and residential construction, additional bank hardening) that further reduces chinook salmon viability in the basin; and 9. Artificial barriers (dams, tide gates, diversions, culverts, pump stations) that prevent juveniles from reaching rearing habitat.
These are not the only problems and they are not entirely independent. They serve as a starting point to guide early actions to protect chinook salmon. Activities undertaken to improve our understanding of the highest priority problem statements, as presented above, will provide critical support to the long-term recovery plan. d) Remaining Critical Habitat and Linkages
Preservation of remaining functioning habitat is typically far more cost-effective than habitat restoration. Protecting these areas is critical to successful recovery efforts and is accorded a high priority by the Technical Committee. Work remains to identify specific sites for preservation and to determine how best to protect them. As a first step, the Technical Committee listed areas of critical habitat in each sub-basin that still support some natural processes. These are summarized in Table 1.
Table 1. Summary of remaining critical habitat and linkages. Sub-Basin Remaining Critical Habitat and Linkages Snohomish River Estuary Wetlands, sloughs, emergent marsh and forested transition zones. Snohomish River Mainstem Forested riparian corridors without dikes or rip-rap, off- channel habitat. Skykomish River Mainstem Forested riparian corridors without dikes or rip-rap, the braided reach. Skykomish River Forks Beckler, Tye, and Foss river catchments; the North Fork Skykomish River to Bear Creek Falls; habitat above Bear Creek Falls. Snoqualmie River Forested riparian corridors without dikes or rip-rap; Griffin and Tokul creek catchments; spawning areas in Snoqualmie, Raging and Tolt rivers. Basin-wide Unditched floodplain tributaries with riparian vegetation.
6. Non-Native Species Concern is growing over the environmental impacts of animal and plant species that originate from other areas. The control and eradication of non-native species poses a serious challenge. The implications of non-native species to an ESA-listed species such as chinook salmon and its ecosystem are unknown at this time because of a lack of data and information. The initial
x Initial Snohomish River Basin Chinook Salmon Executive Summary Conservation/Recovery Technical Work Plan statewide effort has been to establish baseline inventory information in Puget Sound and develop planning and regulatory activities within the context of federal strategy.
7. Data Gaps The Technical Committee identified several important gaps in the available information as it assembled this initial work plan. They are listed in the main document to guide development of a research program to support salmon recovery.
F. ACTIONS Based on the best available scientific information, the Technical Committee has assembled a set of initial actions that could be undertaken to conserve and recover chinook salmon in the Snohomish River basin. These actions are designed to protect and enhance salmon populations and their habitat. The Technical Committee has largely deferred consideration of social, economic and other non-technical impacts. Analysis of those other considerations is an important next step.
Chinook salmon recovery depends on many factors, including harvest, artificial production and habitat management. No single factor can individually bring about successful recovery. The Technical Committee recommends the actions in this document for consideration in developing a chinook salmon conservation and recovery plan.
1. Harvest Management Plan A new chinook salmon harvest management plan should be developed based on a better understanding of the processes that govern population dynamics, once that is available. In the meantime, harvest management should:
1. Maintain the exploitation rate on each brood below a maximum level set such that harvest will not impede the ability of the stocks to rebuild; 2. Maintain escapement for each stock above a minimum level to assure the continued viability of each stock; 3. Reduce fishery-induced size and age selectivity; and 4. Continually monitor the results and modify the plan as required to meet the goals.
2. Artificial Production Management Plan Snohomish River chinook salmon are managed primarily for natural production. Artificial production is provided to achieve defined objectives consistent with the principle that the risks to natural production caused by artificial production will be minimized. The State and Tribal co- managers of the fishery should review existing artificial production programs in the Snohomish River system to identify aspects that could be modified to reduce risks to the natural stocks of chinook salmon. Any newly proposed artificial production projects should be evaluated for risk to wild chinook salmon stocks and approved only if the risk will be minimal. Monitoring of the operations and impacts of the Tulalip and Wallace River hatcheries should be conducted to ensure that the programs are consistent with the recovery of wild stocks.
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3. Habitat Management Plan Based on the guiding principles, the Technical Committee compiled a list of actions to improve salmon habitat. There is no succinct way to summarize the whole list. In keeping with the principle that places primary emphasis on protection and reconnection of habitat, the protection recommendations for each of the nine problem areas are summarized in Table 2. The main document lists many more, including restoration, enforcement, research and education actions.
Table 2. Summary of recommended protection actions for priority habitat problems. Problem Recommended Protection Actions Loss of channel Prevent any additional modification of undisturbed/natural banks in the area and complexity basin. Prohibit floodplain land uses that are incompatible with channel meandering and natural flooding. Identify and acquire stretches of undisturbed river corridor that continue to function unimpaired. Dearth of large Prevent further removal of LWD from stream channels within the basin. woody debris Protect remaining riparian zones to provide a future source of LWD. (LWD) in channel Protect mature riparian forests through acquisitions or easements. Flood flows that Prevent floodplain land uses and practices that are incompatible with scour redds natural processes. Prevent loss of wetlands and side channels and the proliferation of impervious surface in the basin. Maintain forest cover to the greatest extent possible. Acquire floodplain land as open space. Increased sediment Prevent actions in landslide hazard areas that contribute to mass input to streams wasting. Acquire landslide hazard areas. Prohibit logging on sensitive slopes. Require slope stability analysis prior to road building or timber harvesting. Employ innovative road designs to reduce sediment inputs. Poor quality Prevent further clearing or other alterations of forests along streams. riparian forests Locate roads, utility corridors and other infrastructure away from streams and rivers. Preserve remaining healthy riparian forests. Loss of wetlands Prevent the loss of wetlands. Protect sites from deleterious inputs, such as herbicides. Purchase wetlands. In redd mortality Ensure that clearing and other activities do not contribute sediment to due to siltation and streams. Limit location and extent of road building. Prohibit any new water quality bank armoring. Require and enforce best management practices. Urbanization that Limit urban development to areas away from floodplains, riparian reduces chinook corridors, wetlands and headwaters. Maintain stream corridors. Limit salmon viability impervious surfaces. Encourage greater concentration of population in urban areas. Ensure public works activities protect streams. Ensure developments manage storm water to preserve natural hydrographs. Artificial barriers Stop alterations of the floodplain and placement of fish passage barriers. that block juvenile Evaluate fish passage for new projects and use bridges for stream and adult migration crossings.
4. Multi-Jurisdictional Programmatic Assessment Land use and development regulations are two of the most powerful governmental influences that affect salmon habitat. For recovery to take place, current watershed conditions and the
xii Initial Snohomish River Basin Chinook Salmon Executive Summary Conservation/Recovery Technical Work Plan policies regulating them must be changed to reestablish the natural conditions that shaped the evolution of salmon. The Technical Committee recommends conducting a comprehensive multi- jurisdictional programmatic assessment. The results should be used to modify regulations and programs to reduce impacts on salmon habitat.
5. Non-Native Species At this time, the impact of non-native plant and animal species on chinook salmon is not well understood. Additional work will be required to determine what non-native species management actions, if any, will be required at the watershed level.
6. Monitoring and Adaptive Management Adaptive management is an approach that incorporates monitoring to allow activities to go forward in the face of some uncertainty regarding consequences. The key provisions are:
• An explicit hypothesis concerning the objectives of an activity; • Monitoring or research designed to test the hypothesis; and • Provisions for changing the activity in response to information or knowledge gained.
Attempts at recovery should not be delayed until the outcomes can be precisely predicted because the damage to chinook salmon populations and habitat could become irreversible in the meantime. Instead, actions can be initiated while the outcomes are still uncertain, provided that a monitoring and adaptive management strategy can help guide changes to the program based on new information as it becomes available.
G. NEXT STEPS This document is intended to provide a technical foundation for a chinook salmon recovery plan. The actions put forward in this initial work plan are based on technical evaluations. That is, they represent what is best for the fish. Many of the actions have additional policy implications, including costs and benefits, that should be explored before a recovery plan is finalized.
The Technical Committee will present this initial work plan to the Snohomish Basin Salmonid Recovery Forum, a group of elected officials and stakeholder representatives drawn from the Snohomish River basin area. The Forum has chartered a subcommittee, known as the Synthesis Committee, to identify policy implications and implementation alternatives stemming from this initial work plan. Over the next several months, the Technical Committee will work in partnership with the Forum and the Synthesis Committee to transform these initial technical recommendations into a set of specific recommendations for chinook salmon recovery in the Snohomish River basin. The Technical Committee will also identify specific geographical areas that should be considered as high priority areas for recovery actions.
As the initial chinook salmon recovery plan is developed further and implemented, the Technical Committee will begin work on a long-term, multi-species salmonid recovery and conservation plan for the Snohomish River basin, as part of the Tri-County and State effort to recover salmon.
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Initial Snohomish River Basin Chinook Salmon Chapter I Conservation/Recovery Technical Work Plan Introduction
I. INTRODUCTION
A. PLAN FOCUS AND PHILOSOPHY The purpose of this document is to provide a technical basis for a chinook salmon conservation and recovery plan for the Snohomish River basin (Water Resource Inventory Area 7). This document also serves as the technical basis for the recommendation of “Early Action Projects” under 75.46 RCW, the Washington State Salmon Recovery Act. Goals have been established to support two different timelines. This document is part of an initial effort intended to make a significant contribution to chinook salmon recovery in the short term while a longer-term, more comprehensive planning effort continues.
• Initial Goal: Develop a technical work plan to protect, restore and enhance the productivity and diversity of wild chinook salmon stocks in the Snohomish River watershed to a level that will sustain fisheries as well as non-consumptive salmon-related cultural and ecological values.
• Long-Term Goal: Develop a multi-species salmonid recovery plan over a subsequent two to three year time period to protect, restore and enhance the productivity and diversity of all wild salmonid stocks in the Snohomish River watershed to a level that will sustain fisheries and other non-consumptive salmon-related cultural and ecological values. The extended time frame is needed to complete the significantly greater level of technical analysis required to develop a comprehensive, multi-species plan.
This initial plan is intended to serve as a foundation or springboard for the subsequent development of a multi-species salmon recovery plan over the next two to three years. This document does not constitute a chinook salmon recovery plan, but rather a working design for the completion of a more comprehensive effort.
In addition to goals, the Snohomish Basin Salmonid Recovery Technical Committee (hereafter, Technical Committee) adopted five principles to guide its efforts in the development of this initial work plan:
1. Place primary importance and emphasis on the protection and reconnection of habitat;
2. Use historical information on watershed conditions to inform and guide today’s resource management decisions;
3. Preserve and restore the natural ecosystem processes that form and maintain habitat for all salmonids;
4. Use monitoring and assessment to guide adaptive management; and
5. Preserve options for the future.
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B. ENDANGERED SPECIES ACT LISTING In May 1999, the National Marine Fisheries Service (NMFS) listed Puget Sound chinook salmon as threatened under the federal Endangered Species Act (ESA). After the listing, NMFS will issue a draft federal regulation under section 4(d) of the ESA for the purpose of protecting and conserving the species. Activities that harm or take chinook salmon or their critical habitat will be prohibited, but the section 4(d) rule may also list public and private activities that are exempt from this prohibition. The ESA also establishes recovery or conservation plans as a way to define the strategy for recovery of listed species. The long-term goal of the Technical Committee is to contribute to such a plan consistent with ESA requirements.
NMFS uses distinct population groups called Evolutionarily Significant Units (ESU) in administering the ESA. The Puget Sound chinook salmon ESU covers all chinook salmon stocks in the Puget Sound region from the North Fork Nooksack River to the Elwha River on the Olympic Peninsula. This includes the Snohomish River basin (Myers et al. 1998). There are substantial ocean distribution differences between Puget Sound and Washington coast stocks; coded wire tags from Washington coast fish are recovered in much larger proportions from Alaskan waters. The marine distribution of Elwha River chinook salmon most closely resembles other Puget Sound stocks, rather than Washington coast stocks. NMFS concluded that, on the basis of substantial genetic separation, the Puget Sound ESU does not include Canadian populations of chinook salmon. Genetic analysis of Nooksack River spring-run chinook salmon identified them as outliers, but most closely allied with other Puget Sound samples. DNA analysis identified a number of markers that appear to be restricted to either the Puget Sound or Washington coastal stocks (Myers et al. 1998).
In the first half of this century, these fish stocks supported thriving fisheries for sport, commercial and subsistence uses. Declines in abundance have led to increasingly stringent harvest restrictions. A detailed discussion of the population characteristics and the roles of harvest and hatcheries in the basin is presented later in this document.
C. GENERAL BASIN CONDITIONS At 1,856 square miles in area, the Snohomish River basin is the second largest watershed draining to Puget Sound. The basin includes three major rivers flowing from the west slope of the Cascade Mountains: the Skykomish River, the Snoqualmie River, and the Snohomish River. Over 1,730 tributary rivers and streams have been identified in the basin, totaling approximately 2,718 miles in length (Williams et al. 1975).
This large, complex system is a major contributor of water, biota and organic materials to the central Puget Sound marine ecosystem. The Snohomish River estuary, although highly altered for commercial, industrial and port facilities, plays a major role as the freshwater-marine ecosystem interface. This ecosystem supports significant populations of native salmonids including coho, chinook, chum and pink salmon; steelhead, cutthroat, rainbow and bull trout; and mountain whitefish. To better characterize the issues affecting the recovery of salmonids throughout the Snohomish River basin, the Technical Committee divided the watershed into sub- basins (Figure 4).
2 Initial Snohomish River Basin Chinook Salmon Chapter I Conservation/Recovery Technical Work Plan Introduction
Figure 4. Map of Snohomish River watershed with sub-basin boundaries.
• Snohomish River Estuary, including the nearshore marine habitat along the Everett shoreline to Mukilteo and the tidally influenced reach of the mainstem and sloughs up to the City of Snohomish; • Mainstem Snohomish River, from the City of Snohomish to the confluence of the Skykomish and Snoqualmie rivers, including the Pilchuck River; • Mainstem Skykomish River, from its confluence with the Snoqualmie River upstream to the confluence of its north and south forks; • Skykomish River Forks, upstream from the confluence of the North Fork Skykomish River and the South Fork Skykomish River; and • Snoqualmie River, upstream from its confluence with the Skykomish River.
3 Initial Snohomish River Basin Chinook Salmon Chapter I Conservation/Recovery Technical Work Plan Introduction
The Snohomish River basin is also the major source of municipal water supply for Everett and southwest Snohomish County, and it contributes to water supplies in Seattle, Bellevue and King County.
Land uses in the basin, both past and current, include timber production; urban, suburban, and rural residential; light industrial; infrastructure (federal, state, county, and private roads; railroads, gas, water, and power lines); recreational; and agricultural uses. In certain portions of the basin, especially the Snoqualmie, Snohomish and lower Skykomish rivers, fish habitat, riparian, and floodplain conditions have been drastically altered from natural conditions by a century of activities. In other areas, the watershed and riparian processes that affect chinook salmon habitat (such as flows, sediment, and channel conditions) are relatively intact. Conversion of forest and agricultural land to residential, commercial and infrastructure uses is a significant land use change currently occurring in the watershed.
D. TECHNICAL WORK PLAN PROCESS The Technical Committee convened initially in June 1998, and met regularly at two-week intervals. It is composed of approximately thirty representatives of governmental and non- governmental organizations with technical expertise and interest in the conservation and recovery of salmon populations in the Snohomish River watershed. Appendix A lists the Technical Committee members and other contributing authors, including representatives from:
• The Tulalip Tribes • Washington State Departments of Fish and Wildlife and Ecology; Conservation Commission • King and Snohomish counties • Federal Agencies – Environmental Protection Agency, Forest Service, National Marine Fisheries Service • Cities of Seattle and Everett; Port of Everett • Washington Trout • Stillaguamish-Snohomish Fisheries Enhancement Task Force • Snohomish Public Utility District • Snohomish Conservation District
The Technical Committee recognized the need to address the general issues of salmon harvest, hatchery operations, and habitat within the Snohomish River watershed. A hatchery/harvest subcommittee was established to draft portions of this plan for review by the whole Technical Committee. This subcommittee included representatives from the two fisheries co-managing organizations, the Tulalip Tribes and Washington Department of Fish and Wildlife. The subcommittee met outside the meetings of the full Technical Committee, allowing the larger group to focus on habitat-related issues.
In fall 1998, the Technical Committee held a series of five watershed sub-basin workshops to assess habitat conditions and problems, emphasizing chinook salmon. All individuals with expertise in the watershed were encouraged to participate in the workshops, regardless of
4 Initial Snohomish River Basin Chinook Salmon Chapter I Conservation/Recovery Technical Work Plan Introduction whether they were members of the Technical Committee. The information compiled at these workshops and a review of available scientific literature provide a basis for this work plan.
This initial plan was developed on a short time frame that did not allow development of detailed and site-specific solutions to the major causes of chinook salmon decline. Instead, it presents recommendations for broad categories of actions to address habitat problems and a framework for a more detailed effort.
E. STATE AND REGIONAL EFFORTS Salmonids have been listed (or proposed for listing) under the ESA throughout much of Washington State. The State has articulated its strategy for responding to these listings in its statewide salmon strategy, Extinction Is Not An Option. The State plan includes sections for regional response in the central Puget Sound region and for watershed-specific plans. This initial work plan is a first step toward a watershed-specific plan for the Snohomish River basin that will ultimately fit into the State’s salmon strategy.
This work plan also provides source material for a central Puget Sound region response. In 1998, over 400 public and private organizations in the areas covered by Snohomish, King, and Pierce counties came together to form the Tri-County Coalition. This voluntary coalition shares information, develops technical information, coordinates chinook salmon recovery planning and consolidates communication with NMFS within the State’s most populous area. This work plan provides input into the Tri-County Coalition effort.
5
Initial Snohomish River Basin Chinook Salmon Chapter II Conservation/Recovery Technical Work Plan Chinook Salmon Habitat Requirements
II. CHINOOK SALMON HABITAT REQUIREMENTS
Chinook salmon spend the earliest and the final stages of their lives in freshwater river and stream habitats. Like all anadromous Pacific salmonids, chinook salmon rear to adults in salt water, then return to the river basins of their birth to reproduce. The freshwater habitat requirements for chinook salmon are generally well-known. However, there are many subtle and important details regarding the freshwater life history patterns of specific stocks in the Snohomish River basin remain to be investigated. This chapter focuses on freshwater habitat conditions required by adult and juvenile chinook salmon while in freshwater and estuary environments. The timing of river entry, spawning timing, and location regarding specific chinook salmon stocks in the Snohomish River basin are discussed in Chapter IV.
A. LIFE HISTORY PATTERNS Chinook salmon exhibit the greatest diversity of life history patterns of all anadromous Pacific salmonids. During the freshwater portions of their lives this diversity can be characterized by different combinations of the following variables: 1) the time of year at which mature adults enter their natal river prior to spawning, 2) the location in the river basin where they rest (“hold”) while awaiting the proper time and conditions for spawning, and the length of time they hold, 3) the location in the river basin and time of year in which they spawn, 4) the length of time juveniles remain in the freshwater environment prior to entering the estuary and open salt water, and 5) the locations in the basin where juveniles reside and feed during freshwater residence.
Two primary juvenile life history patterns occur in chinook salmon. These are based on the times of river entry and spawning, and are linked to the duration of juvenile freshwater residence. The first life history pattern is commonly referred to as “stream-type.” Adults of this type enter mainstem rivers in late-March through May and spawn between mid-July and early-September. Progeny from these stocks emerge from the gravel between the end of March and early-May of the following spring. Juveniles remain in fresh water for a full year, before smolting and migrating downstream to salt water. A small proportion of juveniles may remain in fresh water until their second year.
The second chinook salmon life history pattern is commonly referred to as “ocean-type.” Adults enter mainstem rivers from July to late-September, and spawn between mid-September and mid- November. Progeny from these stocks emerge from mid-March to mid-April. As a rule, juveniles from these stocks migrate downstream during their first spring and enter the estuary, where they remain until reaching sizes of 2.4 to 2.8 inches. Also, a portion of these ocean-type emergent fry may remain in the river and rear for several weeks to two months and then migrate downstream to the estuary and beyond (Hayman et al. 1996).
B. FRESHWATER HABITAT REQUIREMENTS Freshwater habitat requirements for chinook salmon can be divided into four broad categories: pre-spawning adult holding, spawning, incubation and emergence, and freshwater rearing and migration.
7 Initial Snohomish River Basin Chinook Salmon Chapter II Conservation/Recovery Technical Work Plan Chinook Salmon Habitat Requirements
Environmental conditions required prior to spawning include adequate water quality, flow, and cover. Most chinook salmon stocks that spawn between early August and mid-October enter rivers between one and four months prior to the onset of spawning. During this pre-spawning period they hold in deep pools that have abundant vegetative cover and cool water temperatures. The selection of active spawning sites may occur in proximity to holding locations (Pess and Benda 1994; Bjornn and Reiser 1991). Adults migrating upstream must also have stream flows that provide suitable water velocities and depths for successful upstream passage. The amount of flow within the channel can determine whether adults have access to spawning beds. Also, warm stream temperatures can lead to delays in migration and spawning and disease outbreaks. Water temperatures during the pre-spawning and spawning periods should not exceed 56°F. Mature females suffer pronounced mortality when exposed to temperatures above 56 to 60°F (Rhodes et al. 1994). Optimum water temperatures for chinook salmon spawning are between 42°F and 55°F (Rhodes et al. 1994, Bjornn and Reiser 1991).
Substrate composition, cover, water quality, water quantity and habitat area are important requirements for chinook salmon during spawning. Healey (1991) suggested that fry and smolt production may be more related to the area of good spawning gravel than to the number of spawners. The range of depths, velocities, and substrate sizes preferred by chinook salmon for spawning is very broad compared to other salmon. Gravel sizes suitable for chinook salmon spawning range between 0.5 and 6 inches. Fine particles smaller than 0.25 inches should not exceed 10% of the spawning gravel. Experiments with Snake River fall (ocean-type) chinook salmon eggs (in experimental troughs under controlled conditions) demonstrated that when average gravel particle size was greater than 0.3 inches and percent fine sediment (less than 0.25 inches) was less than 11%, egg survival-to-emergence was greater than 76% (Bennett and Eaton 1996).
Chinook salmon have been documented to spawn in shallow side channels at water depths of 5 inches and in main river channels over 23 feet deep (Vronskiy 1972, Healey 1991). Average spawning depths are in the range of 12 to 16 inches. The best spawning gravel occurs on moderate gradients (less than 3%) (Montgomery et al. 1999). An even flow of cold, well- oxygenated water is required throughout the time that eggs and pre-emergent fry remain buried in the gravel. Stream currents bring fresh oxygen to the eggs and fry, and remove metabolic waste products. Chinook salmon eggs are large and sensitive to reduced oxygen levels. They require substrates with adequate interstitial flow. Current velocities range from as slow as 4 in/s in shallow side channels to as fast as 60 in/s in very deep main channels. Average reported velocities are in the range of 16 to 24 in/s.
After being deposited in the gravel, fertilized eggs will remain buried for 5 to 6 months before alevins hatch, absorb their attached yolk sac, and swim up through the gravel to emerge as fry. Water temperature during the incubation period is critical. Optimal incubation temperatures are between 42 and 55° F.
Other important environmental factors during incubation include the level of fine sediment transported by the river and the frequency, duration and magnitude of flood flows. Siltation in spawning beds can lead to increased mortality of incubating eggs from low dissolved oxygen levels or by entombment (Shaw and Maga 1943; Wickett 1954; Shelton and Pollock 1966).
8 Initial Snohomish River Basin Chinook Salmon Chapter II Conservation/Recovery Technical Work Plan Chinook Salmon Habitat Requirements
Siltation that occurs early in the incubation period causes the greatest negative effect on eggs. Percent of fry emergence decreases when fine sediments in the riverbed reach 10 to 20%. Chinook salmon alevins have a difficult time emerging from gravel when the percent of fine sediment exceeds 30 to 40% (Bjornn 1968). Fine sediment in redds may also affect the size of emergent fry and timing of emergence (Koski 1966, MacCrimmon and Gots 1986). Flooding has been shown to be an important cause of chinook salmon mortality during over-winter incubation and juvenile rearing periods due to high flow velocities and bed scouring (Gangmark and Broad 1955, Gangmark and Bakkala 1960, Seiler et al. 1996, Wales and Coots 1954, and Coots 1957).
Upon emergence fry disburse downstream into summer rearing habitats, primarily at night. The rate of dispersal and migration is generally correlated with flow. Lister and Walker (1966), and Major and Mighell (1969) concluded that the amount of available summer rearing area limits the number of fry that can reside in a stream. Additional fry are displaced downstream. Research in the Snohomish River estuary in 1986 and 1987 indicates that chinook salmon in the basin exhibit both ocean-type and stream-type life history patterns (Beauchamp 1986, Beauchamp et al. 1987).
Considerable evidence indicates that juvenile chinook salmon use several types of stream edge habitats, rather than open-water, main channel habitats. Stream edge habitats can be characterized as bar, bank, and backwater habitats. Bank habitats are either natural or hydro- modified (i.e., rip-rapped or artificially stabilized). Bank habitats have vertical or near-vertical shores; bars have shallow, low gradient interfaces with the shore; and backwaters are low velocity areas separated from the main river channel and connected to the river at or near the downstream end (Hayman et al. 1996). A recent survey of habitat use by juvenile chinook salmon on the Skagit River (Hayman et al. 1996) showed that fry made extensive use of all edge habitats, but displayed clear preferences for backwaters and natural banks.
Optimal water temperatures for juvenile chinook salmon rearing in fresh water are within the range of 50 to 60° F. Extended exposure to temperatures between 61 to 66°F reduces growth and impairs long-term survival (Rhodes et al. 1994).
Cover is an important feature of rearing habitat for chinook salmon. Cover is difficult to define but can include depth, turbulence, large substrate, overhanging vegetation, undercut banks, woody debris, and aquatic vegetation. The number of juvenile chinook salmon remaining in pools increases with increasing amounts of cover (Bjornn and Reiser 1991). Brusven et al. (1986) found that 82% of juvenile chinook salmon preferred stream sections with one third overhead cover to sections without cover. The addition of cover increases the complexity of the space and the number of fish that can live there. Cover needs vary for each juvenile life stage, therefore a complex mixture of cover types needs to be available. In the Pacific Northwest, large woody debris (LWD) is a primary component of cover. It occurs throughout the basin, from headwater streams to the estuary. LWD provides cover and creates a diversity of hydraulic patterns that increase habitat complexity for salmonids and aquatic species.
The amount and quality of pool habitat is also an important habitat element for chinook salmon. The abundance of juvenile chinook salmon in some Idaho streams appeared to be asymptotically related to the size of pools. The number of juvenile chinook salmon increased linearly with increasing pool size up to pools 2000 square feet in surface area (Bjornn et al. 1977). The effect
9 Initial Snohomish River Basin Chinook Salmon Chapter II Conservation/Recovery Technical Work Plan Chinook Salmon Habitat Requirements of reducing space available to fish in small pools was illustrated by Bjornn et al. (1977) in a stream sedimentation study. When sand was added to a natural pool, reducing pool volume by half and the surface area of water deeper than 1 foot by two thirds, fish numbers declined by two thirds.
Along with quantity of pool habitat, the amount of food available is a factor that determines carrying capacity of streams. Production of aquatic invertebrates, that juvenile salmon eat, depends on the amount of organic material available. Chinook salmon food preferences in fresh water include adult and larval insects, amphipods, and small fish. (Mundie 1969, Chapman and Quistdorff 1938, Chapman and Bjornn 1969, and Becker 1973).
C. ESTUARY HABITAT REQUIREMENTS Estuaries, including estuarine marshes and tidal channels, provide important nursery habitat for ocean-type chinook salmon fry (Northcote 1976; Healey 1980b, 1982b; Levy and Northcote 1982). Estuaries provide: 1) a physiological transition zone for adaptation to the saltwater environment (Wedemeyer et al. 1980), 2) important forage areas (Healey 1982, Simenstad et al. 1982), and 3) cover to avoid predators (Simenstad et al. 1982). Adequate growth during river and estuary residence is critical to ensure marine survival because larger juveniles can exploit a wider variety of prey species and are less vulnerable to predation (Beauchamp et al. 1987). Mud and sand flats with depths between 1 and 6 feet (MLLW) are the most productive intertidal areas for the benthic invertebrates consumed by juvenile salmonids (Smith 1977). Tidal sloughs and shallow shoreline areas are also important to juvenile chinook salmon. The influence of LWD to these estuary habitats is poorly understood. However, LWD provides cover and adds to substrate and depth heterogeneity. In salt marshes, LWD traps sediments, which increases the extent of the marsh. In areas of predominantly mud bottom LWD also serves as repository sites for herring spawn (Spence et al. 1996).
Food preferences in estuarine environments include adult and larvae insects, zooplankton, and small fish. Estuary feeding appears to be opportunistic (Healey 1991). Crustacean zooplankton were important in the diet of chinook salmon during July-August in the lower Columbia River (Craddock et al. 1976); juvenile chinook salmon were actively feeding on bay shrimp larvae in the Stillaguamish River estuary (Kirby 1994); juvenile chinook salmon in the lower Chehalis River were feeding on crustaceans and adult and larval insects (Herrmann 1970).
Juvenile chinook salmon growth in estuaries is often greater than river-based growth (Rich 1920a, Reimers 1971, Schluchter and Lichatowich 1977). However, juvenile growth may be disrupted in estuaries when “overgrazing” occurs, which can be caused by large numbers of ocean-type chinook salmon entering the estuary en-masse (Reimers 1973, Healey 1991, NMFS 1998). Large-scale hatchery releases may also result in over grazing (Lichatowich and McIntyre 1987).
Residence time within the estuary appears to depend upon juvenile chinook salmon life history pattern. Ocean-type chinook salmon fry and fingerlings reside in the estuarine region for a longer period of time than the stream-type chinook salmon (Reimers 1973, Kjelson et al. 1982, Healey 1991, NMFS 1998). Stream-type chinook salmon migrate quickly through the estuary, into
10 Initial Snohomish River Basin Chinook Salmon Chapter II Conservation/Recovery Technical Work Plan Chinook Salmon Habitat Requirements nearshore waters and to the ocean (Healey 1983, 1991). However, yearling smolts entered the Snohomish River estuary the second week of April and were found in low numbers for over two months (Beauchamp 1986). Mark recoveries suggest chinook salmon juveniles reside in estuarine tidal channels for at least 1 to 10 days, and juveniles traveled up to 6 miles up and down the sloughs over a period of six to eight days (Beauchamp et al. 1987).
D. SUMMARY Chinook salmon require a very high quality environment throughout freshwater and estuarine areas. This environment consists of multiple habitat types that are used by chinook salmon at various life stages, as they rear to a size at which they smolt and migrate to sea. Historically, where land use activities occur in watersheds, we have often limited our reference of habitat requirements to spawning salmon. The descriptions above indicate that it is necessary to consider the full range of chinook salmon life history stages and patterns to ensure their survival and to restore populations to sustainable production levels. The processes that create such high quality and diverse habitats are discussed in the next chapter.
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Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat
III. PROCESSES THAT FORM AND MAINTAIN HABITAT
A. INTRODUCTION Salmon in the Pacific Northwest have evolved through interactions with their environment. Natural conditions are complex and highly variable across time and space, but are controlled by fundamental physical and geochemical processes.
Environmental conditions were set and periodically reset by large-scale natural disturbances (fires, large floods, volcanic eruptions such as Mount St. Helens) that had recurrence intervals measured in decades to thousands of years (Reeves et al. 1995, Benda et al. 1998). These catastrophic disturbances served to replenish sediment and large woody debris in streams. Natural hydrologic processes subsequent to such events would erode and redistribute sediments and wood, causing a succession of habitat conditions. In addition, these natural events were often not watershed-wide, which resulted in channel conditions that were at different successional points, thereby shaping a diverse channel network. These natural disturbance events may have eliminated or reduced populations in portions of a watershed, but at the same time created new and complex habitats to be colonized later.
Recent human disturbance in the Puget Sound region and throughout the Pacific Northwest, however, has altered the physical, chemical, and biological processes by increasing the frequency of disturbances (e.g. of floods, mass wasting), while restricting or eliminating natural channel and riparian vegetation responses. As a result, human activities have forced chinook salmon to contend with rapidly changing habitat conditions and chronic stresses. To appreciate the significance and magnitude of these changes it is essential to understand the natural conditions and processes under which salmon evolved.
B. NATURAL PROCESSES THAT SHAPED PUGET SOUND RIVERS AND SALMON POPULATIONS Rivers are created and shaped through the interaction of climate and basin geology. The dominant force shaping a river is precipitation. The average annual amount of precipitation, the temporal pattern of its distribution among the months of the year, the spatial pattern of its distribution across the drainage basin, and inter-decadal variations in these patterns are basic climatological variables influencing rivers. Average annual air temperatures and their distribution and variation across the landscape and across decades interacts with precipitation, vegetation, and landscape topography to influence patterns and rates of chemical weathering; this in turn influences the interaction of precipitation with basin geology.
Rainfall and snowfall are delivered to the river channel through surface runoff and groundwater flow. The effect of precipitation on stream flow may be immediate, in the form of overland flow during a rainstorm, or delayed, by being stored and later released to the stream as snowmelt or glacier-melt. The result is a fairly regular, usually annual, stream-flow pattern or hydrograph.
13 Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat
The volume and timing of stream flow interact with local geological features to produce channel patterns and forms that give shape to a river. The headwater streams of the Snohomish River basin originate in a variety of bedrock types and areas of alpine glaciation. The bedrock is generally covered by thin layers of colluvium and alpine glacial deposits. Alpine glaciers cut deep U-shaped valleys of the Skykomish, Tolt and upper Snoqualmie rivers (Pentec 1998). The shape of the lower valleys, rivers and sediments observed today are principally due to glaciation during the Pleistocene era. Glacial sediments and outwash cover much of the landscape. These glacial deposits generally fill low-gradient valley floors to depths of tens of yards. Younger alluvium can be found inset within the glacial deposits at various points along the valley floors.
Among the principal geological features that govern stream channel form are the topographic gradient, which locally governs the slope of the streambed; the resistance of the banks and streambed materials to erosion by water and sediment; and the amount, sizes, and physical/chemical composition of sediments being transported by the water (Church 1992). Streams and rivers transport sediments as suspended sediment, such as fine silt and clay particles, and as bed sediment or bedload, such as sand, pebbles, cobbles, and boulders. Bedload materials slide, roll, and bounce along the river bed.
A river channel continually adjusts its form to inputs of water and sediment that the channel receives along its length and which it must transport or store. Having a dominant role in the adjustments the channel makes is the roughness of the bed and banks and the channel slope. Channel roughness is determined by the rock types making up the bed and bank, as well as the amount and kind of vegetation growing within the riparian zone and the amount of large woody debris stored within the channel (Montgomery and Buffington 1997, 1998; Abbe and Montgomery 1996).
In summary, river channels are the cumulative expression of complex interactions between landform gradient and topography, hydrograph, sediment inputs and vegetation. Understanding how they interact to affect channel conditions and habitat is fundamental to understanding how salmon evolved and what must be achieved at the catchment scale in order to sustain them.
C. THE RIVER CONTINUUM A basic concept of river ecology is that of the river continuum (Vannote et al. 1980, Stanford 1996). According to this concept, river basins must be understood in four dimensions: longitudinal, latitudinal (horizontal), vertical and temporal.
1. Longitudinal Rivers extend from the top of the drainage divide downstream to an estuary or a confluence with another river. The Snohomish River basin, for example, begins on peaks in the Cascade Mountains and ends in Possession Sound. Streams and rivers near the top of the catchment generally have steep gradients and drain relatively small areas. Further downstream, the area drained by streams is larger and the average gradient is reduced.
Streams and rivers in forested areas near the top of the divide generally have steep gradients and drain relatively small areas. These steep mountain streams have the highest erosive power per
14 Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat volume discharge. These streams are sources of sediment and transport a range of sediment sizes downstream. The beds of these streams have a larger proportion of large cobble and boulders (greater than six inches in diameter). Examples would include the upper Beckler, Foss, and Miller rivers. Gravel suitable for spawning by salmonids (approximately one-half inch to three inches in diameter) is usually present only where obstructions in the form of boulders, sharp bends in the channel, or accumulations of large woody debris effectively lower the local gradient (Abbe and Montgomery 1996, Montgomery and Buffington 1998, Montgomery and Buffington 1997).
Reaches further downstream near the transition from foothills to lowland valley floors drain larger areas but have lower overall gradients and proportionately more pebbles, gravel, small cobbles and smaller sediments than smaller, steeper upstream segments. Examples of these would include the Skykomish River from the U.S. 2 highway bridge above Gold Bar downstream to Sultan, and the lower mile of the Tolt River down to its confluence with the Snoqualmie River at Carnation. While steeper headwater stream and river reaches are predominantly sediment sources that transport more sediment than they store, foothill-valley floor transition reaches begin to attain a balance between sediment transport and sediment storage. Moving downstream along these reaches of the longitudinal continuum one will encounter reaches that are predominantly sediment storage areas alternating with reaches that are predominately sediment transport areas.
The furthest downstream reaches on the wide valley bottoms and especially within tidal influence are predominantly depositional segments, with the lowest gradient and the highest proportion of fine sediments (silt, clay, and mud). Reaches with gravel and cobbles suitable for spawning of some salmonid species occur along such segments but are generally more isolated and scattered than in upstream reaches.
2. Latitudinal (Horizontal) Superimposed on a river's longitudinal dimension is a lateral dimension extending from the channel banks out into the vegetated riparian zone and floodplain. This is a zone of important biological and physical interaction between the aquatic and terrestrial ecosystems. Through their roots and leaves, trees and shrubs exchange nutrients with riparian soils and the stream water (Naiman et al. 1998, Tabacchi et al. 1998). Riparian vegetation contributes large wood to the channel that contributes to channel stability, provides habitat structure and cover for aquatic animals, and traps and stores sediment and organic material (Naiman et al. 1998).
During periods of high discharges, floods can extend across entire valley floors. By inundating the riparian zone, over-bank flow can deliver dissolved and suspended nutrients to the floodplain and stimulate significant plant growth. Flood flows also transport nutrients and organic materials that were stored in the riparian zone between floods back to the river channel (Malanson 1993, Naiman et al. 1998, Tabacchi et al. 1998).
Depending on the geology, size and slope of the valley, the river channel can shift horizontally in response to flood flows. This shifting creates new mainstem and off-channel habitat and new land surfaces for riparian vegetation. It also allows the river to access a major source of sediments (Lewin 1992).
15 Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat
3. Vertical The area of active biological and chemical interaction between the river and the land extends below the river bed and beyond the width of the active channel. In streams and rivers traversing large deposits of alluvial gravel, as is the case in most of Puget Sound, there is a large zone of porous bed and bank sediments which regularly exchanges water, nutrients and biomass with the open stream channel. This hyporheic zone stores river water under the open channel and beneath the floodplain at varying scales along the longitudinal continuum of the river. It can be particularly significant in low gradient floodplain segments, extending horizontally beneath the floodplain for over a mile (Stanford et al. 1994, Edwards 1998).
The hyporheic zone expands and shrinks between periods of high discharge or flooding and periods of lower flows. By storing cold water during spring snowmelt and slowly releasing the cold water back to the open channel during base flow, the hyporheic zone moderates stream temperatures during the summer. During winter dry periods, the same is true: hyporheic water discharged to the channel is warmer than water in the open channel.
By moving at a much slower rate than when in the active channel, organic molecules attached to small particles or dissolved in hyporheic water are subject to microbial, particularly bacterial, modification and transformation. The water is biochemically enriched. Such enrichment provides greater nutrients for the support of invertebrates capable of inhabiting the interstitial spaces in the alluvial gravel, and for the roots of riparian vegetation.
Local topography and geology interact to produce alluvial reaches where water in the river channel penetrates and downwells into the hyporheic zone and others where hyporheic water returns to the open channel (upwells). Upwelling zones where microbially-enriched hyporheic water returns to the channel are often biologically productive and are preferred salmonid spawning sites within a river reach (Stanford and Ward 1992; Edwards 1998).
4. Temporal The biological and physical gradients that occur along the longitudinal, latitudinal and vertical dimensions vary across time. Changes occur seasonally, as well as on scales of decades and centuries. The temporal variability experienced along each of the three spatial dimensions is a critical feature of the biological and physical processes that shaped salmon evolution.
D. FLOODPLAIN HABITAT FORMATION AND USE The valleys of the Snohomish, Skykomish, and Snoqualmie rivers were shaped in significant ways by the Pleistocene glaciation of the northern Cascade Range and the Puget Sound lowlands and by the fluvial processes of cut and fill that have reworked this glacial legacy (Booth 1990). Over time, these processes produced a wide variety of physical and biological habitat conditions across the floodplain. These habitat conditions change across a range of temporal scales, producing a dynamic mosaic of terrestrial and aquatic environments.
As the river produces and maintains its channel along the course of the valley and across its breadth over time, it reworks deposits by alternately cutting through older elevated terraces and
16 Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat filling previous channels. This process of cut and fill is a basic feature of all rivers (Stanford 1996).
The basic processes of cut and fill enable the river to achieve a dynamic balance between the transport and deposition of its sediment load and the restrictions imposed upon channel migration by the river's valley, bed and bank geology, and riparian zone. This results in complex sinuous channel forms in low gradient valleys in which meandering and braiding predominate. As these channel forms are created and maintained, the river moves back and forth across its valley and in the process creates its floodplain (Lewin 1992, Leopold et al. 1964).
The common meandering, "S-shaped" channel, deep along the outer bends with shallow, gently sloping sand/gravel bars on the inside bends, exhibits the basic floodplain creation process most clearly. Along the outside bend, the river "eats" away at the bank sediments, moving the channel in this direction and moving the outside point of the bend downstream over time. This primarily takes place on an annual basis during times of high discharge when the river reaches the tops or overflows its banks. As it does so, it deposits suspended and bedload sediments along the gently- sloping inside bends, and flood flows deposit finer suspended sediments onto the valley floor adjacent to the channel. The sediments eaten away by the river at the outside bend tend to be deposited on the same side of the river, downstream at the next gently-sloping bar where the outside bend of the "S" has switched to the opposite side (Leopold 1994, Leopold et al. 1964).
Suspended fine sediments deposited onto the top of the floodplain by the river during periods of over-bank flow contribute significantly to the development of valley/floodplain topsoil and enables pioneer riparian plant species like willows, alders, and black cottonwoods to take hold on the land adjacent to the river channel. Decayed organic matter from these plants contributes further to the development of nutrient-rich topsoil, facilitating the establishment of additional riparian species, particularly evergreens.
Over a period of several thousands of years within a particular climatic regime, the active channel of large floodplain rivers like the Snohomish, Skykomish, and Snoqualmie rivers will have occupied nearly every lateral segment of the valley floor. Annual lateral channel migration rates can be astoundingly rapid, with rates measured in tens of yards (Abbe and Montgomery 1996). In many places, the river will have reworked and sorted previous glacial and alluvial deposits. This results in sediments of different sizes underlying the floodplain, with porous gravel predominant where the major channels used to flow. These areas become zones of preferential flow (Huggenberger et al. 1998) that actively exchange groundwater with the open channel. These hyporheic zones can harbor extensive communities of aquatic fauna, bacteria, and algae, many members of which live out major parts of their life cycles in and near the open surface channel (Stanford et al. 1994, Edwards 1998).
Where zones of preferential flow lie close to valley walls and close to the surface of the floodplain, groundwater from upland percolation flowing through unconfined aquifers can enter and mix with water from the active channel flowing through these zones. The water may come to the surface as springbrooks (also called wall-based channels), which flow across the floodplain to join the open river channel.
17 Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat
River meandering across the floodplain produces a complex legacy of braided channels, side channels, springbrooks, and back channels together with their abandoned remnants such as oxbow lakes and dead arms (Stanford and Ward, 1992). Braided channels are river segments possessing two or more main channels and lacking a clear main channel, such as the Skykomish River between Gold Bar and Sultan. Braided channels occur in valley segments of relatively high gradient, hence relatively high river energy, but where the river channel is actively aggrading due to an excess of sediment supply relative to the river's sediment transport capacity (Church 1992, Creuze’ des Chatelliers et al. 1994). Fine sediments get transported through such segments and the bed is predominantly gravel and cobbles (1/2 to 6 inches in diameter) through which the river cuts multiple channels of relatively equal size.
Braided reaches of the main channel provide diverse rearing habitat for juvenile chinook salmon and steelhead trout during periods of normal flow. These reaches contain numerous gravel islands and mid-channel gravel bars that develop into islands by trapping logs and additional alluvial gravel. (Malanson 1993, Fetherston et al. 1995, cited in Naiman et al. 1998, Abbe and Montgomery 1996). Locally, these bars and islands are colonized first by cottonwood, alder and willows, and eventually by evergreens such as fir, cedar, hemlock, and spruce.
The numerous narrow channels in braided river segments are afforded significant shade by these mature riparian trees which develop on stable gravel islands. Historically, such wooded islands in braided river segments reproduce many of the characteristics of off-channel habitat on the floodplain itself, and increase the length of natural bank habitat.
More than other species of salmon, chinook salmon are capable of using a wide variety of gravel sizes, current velocities and depths for spawning (Vronskiy 1972, Healey 1991). By providing a variety of channel and substrate sizes, depths, and velocities, braided reaches provide a variety of spawning habitat for chinook salmon.
Chinook salmon are, however, primarily main channel spawners that tend to favor channels with moderate to large substrate sizes (1 to 6 inches), water depths of 18 or more inches, and current velocities between 1.5 and 3 feet per second (Healey 1991). Braided reaches and the processes that create and maintain them are critical for maintaining the supply and transport of high quality spawning gravel to lower gradient reaches further downstream. Braiding and channel meandering enable the river to access alluvial gravel buried beneath the floodplain (Lewin 1992). This increases the ability of the river to transport spawning-gravel-sized sediments to downstream main channel reaches during high discharge events.
Side channels are small flowing channels connected to the main channel at both the upstream and downstream ends. They are generally produced and maintained by over-bank flows. Such flows produce side channels in one of two ways: by an avulsion at the upstream entrance at which the river is able to cut a minor channel downstream through the floodplain surface and back to the main channel; or by initiating an avulsion at a weak point on the floodplain adjacent to the main channel which then works its way up the floodplain and connects to the main channel upstream of the initial avulsion.
18 Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat
Side channels provide spawning habitat for adults and significant rearing habitat for juvenile salmon due to generally lower stream velocities that result from both the smaller channel size and the trapping of large woody debris (logs and root wads) from the adjacent riparian zone. Large woody debris, extensive riparian vegetation and narrower channels often provide more shade and cover in side channels than in main channels.
Back channels are channels that are connected to the main channel only at the downstream end, such as Haskell Slough on the Skykomish River. They are often former side channels that have lost connection to the main channel at the upstream end. A back channel may be completely lacking in flow or may have flow as a result of hyporheic water upwelling into it at the upstream end. In this latter case, the back channel can be considered a type of springbrook.
Springbrooks and back channels provide additional habitat conditions for juvenile salmonids. Lacking an upstream surface connection to the main channel, these off-channel areas provide greater refuge from high current flows during the winter and spring. Springbrooks and, where upwelling groundwater is present, back channels provide seasonal thermal conditions that are otherwise unavailable to salmonids during extreme thermal conditions that occur during winter and summer. Springbrook temperatures can 15°F or more cooler than temperatures in the main river channel and in side channels during July and August. During the winter, these areas can be 5°F or more warmer than water in main channels and side channels. Springbrooks and back channels can remain open when side channels are frozen over and edge ice forms along the main channel. The moderate temperatures are much closer to the thermal optimum for salmonids than those in the active channel.
Springbrooks and back channels where upwelling of groundwater occurs are often more biotically diverse than the main channel and side channels. Hence, they often provide both more food items and food items of a higher quality than elsewhere along the floodplain.
Most aquatic creatures that live near and along the floodplain are thermal conformists ("cold- blooded"), i.e. not capable of maintaining constant internal body temperatures independent of ambient environmental conditions. Their metabolisms fluctuate widely in direct response to ambient environmental temperatures. In order to accommodate a wide variety of organisms with differing thermal/metabolic requirements at any one time, the floodplain must provide a diversity of environmental temperature niches within a relatively small area. The diversity of floodplain aquatic habitat described herein in conjunction with the diversity of riparian plant communities on the floodplain is essential to providing the requisite diversity in habitat temperatures.
When considered in their entirety, these several floodplain aquatic habitat types provide a wide diversity of physical and biotic conditions with regard to temperature, cover, current velocity, nutrients and food organisms. This diversity in turn is capable of supporting considerable diversity and abundance of salmonids and other fishes together with numerous species of amphibians, birds, and mammals.
19 Initial Snohomish River Basin Chinook Salmon Chapter III Conservation/Recovery Technical Work Plan Processes that Form and Maintain Habitat
E. SUMMARY: NATURAL HABITAT DIVERSITY AND DYNAMISM The habitat diversity described above, which characterized the Snohomish River floodplain prior to major human immigrations in the past 150 years, was created and maintained by a variety of complex and interacting physical processes. The operation of these processes requires a normal hydrologic regime in which annual winter rain-on snow events and/or spring snow-melt runoff produce relatively rapid increases in river discharge leading to over-bank flood flows of varying levels of severity. These events are followed by relatively prolonged, gradual recession. Bank- full and over-bank flows are required to shape and maintain both the active channel and the various off-channel habitat types by regularly mobilizing and transporting fine sediments which accumulate in the channels between peak flow events. Prolonged recession permits flood flows of cold water to fill the interstitial spaces under the active channel and the floodplain surface which are then subsequently able to release cold water to off-channel habitat and to the main channel during the low-flow period of the hot summer months.
Over-bank flows must spill over the floodplain to deposit fine suspended sediments outside of the active channel. The active channel needs to be free to erode its banks and move laterally into the adjacent riparian zone, which simultaneously allows the river to add to the floodplain along the opposite bank.
Historically, floodplain habitat constituted a changing mosaic of tree and shrub communities and of channel shapes and off-channel habitat types in different stages of maturity at any given time. Each of these stages contributed important elements to the overall integrity of the floodplain ecosystem which particularly nourished and sustained chinook salmon populations. The entire floodplain ecosystem was the product of dynamic physical, chemical, and biological processes, briefly outlined above, operating across several temporal and spatial scales.
20 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population
IV. STATUS OF THE POPULATION
A. SPECIES COVERED This report covers only the chinook salmon (Oncorhynchus tshawytscha) populations that spawn and rear in the Snohomish River system. The approximate extent of the known distribution is shown in Figure 5.
Figure 5. Approximate extent of known current chinook salmon habitat.
21 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population
B. POPULATION SIZE The NMFS status review of chinook salmon (Myers et al. 1998) provided general information on the historical abundance and characteristics of Puget Sound chinook salmon. There is little additional information specific to the Snohomish River system. Snohomish River chinook salmon population size estimates are based on annual estimates of spawning escapement. Escapement numbers are estimated using a combination of foot surveys, aerial surveys, and direct counts (natural spawning fish are counted when they are transported over Sunset Falls). Smith and Castle (1994) describe chinook salmon escapement estimation methods in detail.
Table 3. Estimated natural spawning escapement of chinook salmon by stock. Stock System Year Snohomish Snohomish Wallace R. Bridal Veil Total* R. Summer R. Fall Summer/Fall Creek Fall 1965 1,593 850 1,864 911 5,443 1966 2,410 1,807 2,403 959 7,929 1967 510 520 863 1,327 3,320 1968 950 1,145 1,552 1,361 5,214 1969 440 639 525 1,856 3,700 1970 1,532 1,323 539 2,110 5,724 1971 1,793 1,211 2,519 1,981 7,822 1972 605 506 231 1,696 3,128 1973 1,306 1,023 409 1,515 4,841 1974 2,102 1,602 109 1,860 6,030 1975 1,290 1,453 139 1,045 4,485 1976 1,117 2,159 135 1,154 5,315 1977 2,613 1,600 613 691 5,585 1978 1,593 3,174 2,468 573 7,931 1979 2,256 1,089 1,513 851 5,903 1980 1,318 2,317 2,085 779 6,460 1981 500 1,449 748 633 3,368 1982 1,045 1,370 1,823 260 4,379 1983 983 2,106 1,155 293 4,549 1984 560 1,697 940 287 3,762 1985 1,093 N/A 2,055 432 4,873 1986 815 2,287 445 727 4,534 1987 1,650 1,587 885 458 4,689 1988 1,093 1,376 607 791 4,513 1989 361 1,840 373 516 3,138 1990 623 2,685 370 613 4,209 1991 1,142 908 200 603 2,783 1992 413 1,160 203 612 2,708 1993 447 2,725 109 630 3,866 1994 968 1,151 468 564 3,626 1995 546 1,160 280 1,036 3,176 1996 1,315 1,648 713 860 4,851 1997 263 2,447 713 744 4,292 1998 1,113 2,695 1,543 572 6,304 * The system total does not equal the sum of the sub-basin estimates because some escapement is not accounted for in any sub-basin.
22 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population
Table 3 lists estimated escapement of naturally spawning chinook salmon by stock for the Snohomish River system for 1965-1998, and Figure 6 shows the same data graphically. The escapement goal for the system was the 12-year average estimated escapement for 1965-1976. The 12-year average of 5,250 spawners was used as a surrogate for the maximum sustainable yield (MSY) escapement goal because 1) there are not sufficient data available on productivity to estimate a true MSY goal and 2) it was Washington Department of Fisheries’ (WDF) assessment (Ames and Phinney 1977) that this population was at productive levels at that time.
9,000 Snoh. Summer 8,000 Snoh. Fall Wallace River 7,000 Bridal Veil Creek System Total 6,000 12-Year Moving Ave. 5,000
4,000
Number of Fish of Number 3,000
2,000
1,000
0 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 Year
Figure 6. Estimated natural spawning escapement of chinook salmon by stock. The goal was exceeded in 1998 for the first time since 1980. The most recent 12-year average (1987-1998) naturally spawning escapement for the system is 4,013 fish (Table 3).
C. DELINEATION AND CHARACTERISTICS OF STOCKS The naturally-spawning chinook salmon in the Snohomish River system are divided into four stocks: Snohomish River summer, Snohomish River fall, Bridal Veil Creek fall, and Wallace River summer/fall (WDF et al. 1993). This stock delineation was based on differences in spawning timing, geographical spawning distribution, and genetic differences as determined by allozyme electrophoresis. Chinook salmon exhibit two fundamental life histories, ocean-type and stream-type, that relate to the length of residence in fresh water during the juvenile life history phase. Puget Sound stocks currently tend to mature at age 3 or 4 and exhibit similar, coastal-oriented ocean migration patterns.
23 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population
1. Snohomish River Summer The Snohomish River summer stock spawn primarily during the month of September, with the spawning taking place in the mainstem Skykomish and upper Snohomish rivers (WDF et al. 1993). Returning adults are often seen in the river as early as late May, with most fish likely entering the river in late June and July. The genetic baselines for the summer hatchery chinook salmon (sampled in 1987 and 1988) and the natural summer chinook salmon (sampled in 1989) were found to be similar (Anne Marshall, WDFW, memorandum 1 August 1997).
The average escapement for the 1965-1976 base period for the summer population was 1,304 fish (Table 3). The escapement of this stock has exceeded this level only twice since 1980. The most recent 12-year average (1987-1998) escapement for this stock is 827 fish, and the 1997 observed level of 263 fish is the lowest on record. The size of the spawning escapement appears to have been declining slowly over the past decade or more. Because of the proximity of the natural spawning area to the Wallace River hatchery, there may be significant straying of hatchery fish into the spawning area. If this is the case then the actual rate of decline of this stock is greater than what would be inferred from analysis of spawning escapement estimates alone.
While there is only limited scale information available, as much as one third of the returning adults from this stock may have a “stream-type” life history, that is, they reside in fresh water for a year or more before migrating to the sea (WDFW unpublished data). This rate is higher than typically reported for most Puget Sound chinook salmon stocks (mostly fall stocks) and illustrates the importance of over-winter and over-summer rearing habitat in the Skykomish and Snohomish rivers. Freshwater rearing habitat preferences for stream-type chinook salmon are poorly understood, but they are thought to require complex habitat structures in 3 to 6 feet of low velocity (up to 1 foot per second, [Healey 1991]) waters. The kinds of habitat that would be likely rearing habitat in the upper watershed would be boulder complexes and complex woody debris (root wads, jams etc.). In the lower river the majority of potential rearing habitat is limited to embedded large wood.
Because Snohomish River summer chinook salmon exhibit a distribution of life histories different from the majority of Puget Sound chinook salmon (mostly fall, predominantly “ocean- type”), it is possible that the various fisheries exploit these fish differently than other stocks. A review of the coded wire information from the Wallace River hatchery summer stock sheds some light on the fisheries that have the greatest impacts on the stock. Although specific information pertaining to the summer stock is not available, the recreational fishery was a major harvester of the Snohomish River summer/fall in Washington waters prior to additional chinook salmon restrictions in the late 1990s.
Over time there appears to have been an upstream shift in the location of the chinook salmon spawning for this stock. In the early 1950s it was reported that 30% of the spawning occurred downstream of Monroe, 54% between Monroe and Sultan, and 16% between Sultan and the Skykomish River forks (WDF 1956, page 39). Forty years later, the distribution of spawning has shifted upstream. The average by section for 1993 and 1994 (the only years that the data breakout allows for a comparison) was 2.5% downstream of Monroe, 41% between Monroe and Sultan, and 56.5% between Sultan and the forks. The latest spawning surveys indicate that this pattern has continued. The cause for this shift is unknown but it may be related to changes in the
24 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population gravel quality and stability and/or perhaps influence of hatchery spawners near the Wallace River hatchery.
2. Snohomish River Fall The Snohomish River fall stock is found in the Snoqualmie River and its tributaries, Sultan River, Pilchuck River, Woods Creek and Elwell Creek, with the majority of the population being found in the Snoqualmie River portion of the basin (WDF et al. 1993). The fall stock begins spawning in late September and spawns through October, with the individuals from the Snoqualmie River portion of the population observed spawning until mid-November or later. The genetic baseline for the Snoqualmie River portion of this population indicates that it is distinct from the other Snohomish River basin populations as well as the hatchery fall stock (Anne Marshall, WDFW, memorandum, 1 Aug. 1997).
The average escapement for the 1965-1976 base period for this population was 1,187 fish (Table 3). In contrast to the general downward escapement trend for chinook salmon in the basin, the escapement trend for this component has been increasing. The most recent 12 year average escapement (1987 to 1998) is 1,778 fish (Table 3), a 50% increase over the base period. The range of escapements in this most recent time period has been from a low of 908 to a high of 2,725 fish. This positive trend is somewhat surprising as it is thought that the Snoqualmie River portion of the basin was suffering from more frequent flooding and other habitat problems than the rest of the basin. Preliminary results from the analysis of otoliths for the 1997 escapement year showed that 93% of the natural spawners for this stock were naturally-produced with the remainder being accounted for mainly by strays from the Tulalip hatchery, with a minor contribution from the Wallace River hatchery.
More scale information is available for these fish than for the Snohomish River summer chinook salmon, although there are still not sufficient data to construct brood year tables. The returning adults have a surprisingly high percentage (typically 25%-30%) of stream-type rearing history for a fall chinook salmon stock (WDFW unpublished data). As with the summer chinook salmon stock, this illustrates the importance of freshwater rearing habitat for this stock. Because these fish exhibit a life history pattern different from most Puget Sound chinook salmon, they may be exploited differently in the various fisheries than other Puget Sound fall stocks.
The limited life history information indicates that yearling rearing habitat is critical for this stock. With most of the banks of the Snoqualmie River confined by levees, the complex habitat needed for juvenile chinook salmon rearing may have been greatly reduced. Because much of what is thought to be typical juvenile rearing habitat for the yearling chinook salmon is lacking, it appears that much of the extended juvenile rearing currently occurring must be in the embedded woody structures located in the lower river. This woody material appears to be quite old and only a very limited amount of this type of material is currently being recruited to the system. Maintenance of existing material and recruitment of new material is critical.
Key spawning areas (Tokul Creek, Raging River, Tolt River, and the mainstem Snoqualmie River immediately downstream of these tributaries) are vulnerable to habitat alterations. The increased bed load movement within the Raging and Tolt rivers coupled with their confined
25 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population channels (dikes) has brought about pressures for flood control activities including dredging of the channels. Maintaining these key spawning areas in this low gradient stream is key to maintenance of naturally reproducing chinook salmon in the Snoqualmie River.
The current flow management practices from the Henry M. Jackson project have resulted in a much more stable situation for chinook salmon using the Sultan River than in the past. A potential concern is that higher than historical fall flows of water cooler than the Skykomish River may result in increased straying of hatchery fish into the Sultan River. Recent sampling for otolith-marked hatchery fish will help shed light on this issue.
Low flows in the Pilchuck River, Raging River, Elwell Creek, and Woods Creek appear to often limit chinook salmon access to these areas.
3. Bridal Veil Creek Fall The Bridal Veil Creek stock has been defined as those chinook salmon that spawn in Bridal Veil Creek (a South Fork Skykomish River tributary), South Fork Skykomish River (below and above Sunset Falls), and the North Fork Skykomish River upstream to Bear Creek Falls (WDF et al. 1993). The fish spawning in Bridal Veil Creek spawn later than the Snohomish River summer stock with peak spawning in the second week of October. Historically, Sunset Falls on the South Fork Skykomish River was a barrier to all anadromous fish. Adult chinook salmon have been transported over Sunset Falls annually since 1958 (Seiler et al. 1981 and WDFW internal information). Numbers transported have ranged from 47 the first year to an average of 1,300 per year during the peak years of 1969-1974. In recent years, approximately 500 chinook salmon per year have been transported. The chinook salmon that have colonized above Sunset Falls are thought to be primarily fish produced in the Skykomish River and its forks. Only fish from Bridal Veil Creek itself were included in the genetic analysis of this population (WDF et al. 1993). The fish above Sunset Falls were included in the brood stock used in the development of the Wallace River hatchery summer stock.
The past spawning ground surveys don’t allow tracking the escapements over time like the other stocks. The counts at Sunset Falls offer the best information on long-term trends. This information must be used with caution since a number of fish were taken from the trap and used at the Wallace River hatchery as brood stock in the late 1970s and early 1980s.
The information indicates that the counts have dropped substantially since the mid-1970s (Table 3). The average number of fish passed above Sunset Falls in the 1965-1976 base years was 1,481; the recent 1987-1998 average has been only 771.
The limited information that is available on the chinook salmon smolts produced above Sunset Falls is from coho salmon smolt trap data collected from 1978 to 1982 (Seiler et al. 1981, 1984). This indicates as elsewhere in the basin that the proportion of production from yearling smolts is greater than generally observed in other Puget Sound systems.
The limited information that is available (mostly anecdotal) indicates that chinook salmon use in the North Fork Skykomish River has declined substantially in the last 20 years. There currently appears to be little chinook salmon use except for the lower mile below Index. Less than one
26 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population redd per year is seen in the upper four miles of the North Fork Skykomish River. Twenty years ago, 10 to 20 adults were seen in the same area. The cause for this decline is unknown.
Another issue that is important for this stock is high turbidity. Bridal Veil Creek suffers from high turbidity caused by the clay banks along the stream.
4. Wallace River Summer/Fall The Wallace River chinook salmon are considered to be a mixture of stocks resulting from hatchery straying and natural production (WDF et al. 1993). This population is considered to be a hybrid stock of hatchery fish (Snohomish River summer and Green River fall stocks) and wild stock (Snohomish River summer). The spawning area is limited to the Wallace River (mostly in the four miles downstream of the hatchery), and the spawning timing covers both the summer and fall time periods.
Beginning with the 1997 brood year, the timing of egg takes at Wallace River hatchery was adjusted so that all eggs are taken during the time the return will be dominated by summer run fish. Summer run production at the hatchery originated from the South Fork Skykomish River, while the fall run production originated at the Green River hatchery, which is out of the Snohomish River system. This action was called for in a memorandum of understanding between WDFW and the Tulalip Tribes (August 27, 1997) because of a desire to eliminate out- of-system brood stock from the Wallace River hatchery.
While this stock was considered healthy by WDF et al. (1993), recent escapements have been down from the 1965-1976 base year period. The base year average escapement was 941 fish, while the recent 1987-1998 average has been 434 fish (Table 3). Preliminary results from 1997 otolith sampling provided an estimate that 60% of the natural spawners in the Wallace River were of first generation hatchery origin. Similarly, approximately 12% of the escapement to the hatchery rack were estimated to be naturally-produced. These results suggest that the chinook salmon in the Wallace River have been a mixture of hatchery and wild production for many years. It is possible that reductions in hatchery production account for the decline in escapement.
The issue of passage past the hatchery rack in the Wallace River should be resolved. Recently some adults have been allowed access to the upper river and some protocol needs to be developed to determine the method and number of fish to pass above the rack. The simplest method would be the complete removal of the rack; however questions remain on the ability of the hatchery to collect needed brood stock and disease issues. There is also some evidence and thought that chinook salmon spawning above the water intake would increase the incidence of diseases, especially Cryptobia, a blood fluke.
5. Possibility of Spring Stock Based on anecdotal information, it is likely that adult chinook salmon in the 1930s and 1940s were entering the river as early as May. Whether these were a separate spring stock or an early timed component of the summer stock is impossible to establish based on available information. Today there are clearly chinook salmon in the basin during the typical spring stock river entry time (April through June). Adults have been seen in the Wallace River during steelhead trout
27 Initial Snohomish River Basin Chinook Salmon Chapter IV Conservation/Recovery Technical Work Plan Status of the Population surveys in late May, and they are occasionally caught by anglers targeting steelhead trout in early June. Are these early fish a true spring stock or just the first of the returning summer stock? They have been seen in the Wallace River downstream from the hatchery, which suggests that at least some of them are summer stock.
Any Snohomish River spring chinook salmon would be expected to spawn in a similar time period as the Skagit River spring stock, typically late July through early September (WDF et al. 1993). In north Puget Sound streams they are usually found further upstream and in cooler water than other chinook salmon stocks. Spawning areas of spring chinook salmon spawning are often at the upper limit of pink salmon spawning areas and the lower limit of Dolly Varden/bull trout spawning areas. They often overlap with steelhead trout spawning areas.
The uppermost historical chinook salmon spawning area in the basin is above Bear Creek Falls on the North Fork Skykomish River. Because of its location it likely had the coolest waters. This area is above pink salmon use and is used by both summer steelhead trout and Dolly Varden/bull trout. Twenty years ago chinook salmon were reasonably abundant in that area, but now they are rarely seen. While that area is not surveyed for chinook salmon, since 1988 it has been surveyed annually for Dolly Varden/bull trout spawning. An occasional chinook salmon and large redds (only one or two) are seen on the first surveys of the year in the upper four miles of the anadromous section of the North Fork Skykomish River. These redds appear to be constructed in August. The August 31, 1989 survey found two fresh redds with no fish on either. A review of existing chinook salmon spawning information for the Snohomish River basin revealed little other indication of spawning prior to September. If spring chinook salmon exist in the basin today they are present in extremely low numbers. They most likely would be found in the North Fork Skykomish River above Bear Creek Falls. However, the State currently does not recognize the existence of spring chinook salmon in the Snohomish River system (WDF et al. 1993).
28 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
V. FACTORS AFFECTING THE POPULATION
A. HARVEST, HATCHERIES, HYDROPOWER AND HABITAT Factors affecting salmon are commonly grouped into four categories: habitat (both freshwater and marine), hydroelectric operations (and the effects of dams in general), hatcheries (including other artificial production programs) and harvest. These “four H’s” have all played a role in the decline of salmon, and they must all play a role in salmon recovery. Changes in one area cannot bring about successful recovery unless the others are also changed to support recovery. Each of these areas is considered in detail in the following sections.
There are other factors beyond human control, such as ocean cycles, that affect salmon populations. Managers must recognize these and act accordingly to preserve the habitat and population base for survival during poor times as well as during boom periods.
B. HARVEST Chinook salmon from Puget Sound are harvested throughout nearly their entire period of marine residency in a plethora of fisheries ranging geographically from Alaska to the ocean off the Washington coast and inside Puget Sound. In most cases, fishing mortality on Snohomish River basin chinook salmon is incidental to fisheries targeting other stocks or species.
Local fish managers (WDFW and Tulalip Tribes) have already begun to make changes to reduce fishing pressure on depressed stocks. Retention of chinook salmon is not currently allowed in recreational fisheries in the Snohomish River terminal area (including the river and nearby marine waters), except in specific locations and times when hatchery-produced fish can be targeted with minimal impact on wild chinook salmon. In the Snohomish River terminal area, the net fishery directed at wild chinook salmon has not been opened since 1984.
In recent years, the only directed fishery on chinook salmon in the terminal area has been on Tulalip Bay hatchery stocks. The Tulalip Tribes conduct a fishery to target fall chinook salmon produced at the Tulalip hatchery. Three strategies minimize the interception of non-target wild chinook salmon in this fishery:
• The fishery is conducted during the time the hatchery fish return to Tulalip Bay.
• The open area is restricted to the extreme terminal area to which the hatchery fish are returning.
• The fishery is open only part of the week to allow opportunity for non-local fish to pass through while local fish accumulate.
These strategies can be evaluated by sampling the catch for otoliths since all Tulalip and Wallace River hatchery production has been mass-marked. Preliminary results from 1997 sampling indicated that 97% of the catch of age 3 and 4 chinook salmon (age 5 fish were not marked in the
29 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
1997 return) in this fishery were of Tulalip hatchery origin. This fishery was sampled again in 1998, and sampling for 1999 is funded and planned.
The U.S./Canada Treaty resulted in reduced exploitation rates on depressed Snohomish River chinook salmon stocks. The terminal area management described above is required under the Pacific Salmon Treaty so that savings of wild fish realized by cutbacks in the ocean and pre- terminal mixed-stock fisheries will be passed through to spawning escapement. Natural spawning escapement for Snohomish River chinook salmon has recovered somewhat from the all-time low in 1992, in part due to reductions in pre-terminal (including Canadian) harvest rates and the success of the pass-though management in the terminal areas.
Even with the cessation of directed fishing, incidental harvest rates can be significant. Incidental harvest in net fisheries directed at other species or at hatchery fish is carefully monitored and planned so that total impact rates will stay below guideline levels. The challenge has been to find ways to allow fishing on abundant stocks and species while minimizing the mortality of Snohomish River chinook salmon.
Because of the lack of a specific indicator stock for Snohomish River summer/fall chinook salmon, it is difficult to estimate the total exploitation rate or the distribution of fishing mortality for this unit. However, using the Pacific Salmon Commission’s (PSC) chinook salmon model, the Puget Sound Salmon Stock Review Group (PSSSRG 1992) estimated that fisheries in Canada took 61% of the harvest of Snohomish River chinook salmon in 1980, declining to 40% by 1990.
From the 1977 through the 1992 brood year, exploitation rates1 on the Snohomish River summer/fall chinook salmon management unit are estimated to have declined steadily from approximately 80% to approximately 55% (PSC 1998). The rates for the 1993 and 1994 brood years were likely even much lower (as low as one-half the 1992 brood year rate) due to major new restrictions in Canadian fisheries and significant changes in Washington mixed-stock fisheries2. The absolute exploitation rates estimated by the PSC model include a high level of uncertainty because factors such as incomplete assessment of the escapement of coded-wire- tagged fish and differential harvest rates on different sizes, ages, and sexes of fish aren’t considered in the model3. However, the trend is clear: despite a gauntlet of mixed-stock fisheries operating, in some cases, for several years on the same brood of chinook salmon, managers have been successful in achieving large harvest rate reductions.
1 This is a so-called “adult equivalent” exploitation rate, computed from the model used by the Pacific Salmon Commission’s chinook salmon technical committee. It measures all sources of fishing-induced mortality (including both retention and non-retention mortality) as (R-E)/R, where R is the total number of fish that would have returned to spawn naturally in the absence of fishing and E is the estimated natural spawning escapement. 2 Based on fishing plans for the 1998 season the average exploitation rate for Puget Sound natural chinook salmon management units was projected at 28%, with approximately 1/2 this mortality occurring in Canadian fisheries. However, the actual fishing mortalities imposed in 1998 were lower than the preseason expectations (on both sides of the border). Post-season estimates of brood year exploitation rates will not be available for several years pending completion of brood recruitment and analysis of coded-wire tag data. 3 The models should be revised to reflect the rates of exploitation on older fish and on females to better assess the fisheries’ success in getting numbers of eggs on the spawning grounds.
30 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Exploitation rates are expected to decline much further for brood years subsequent to 1992 because of new management guidelines and greater fishery restrictions implemented beginning with the 1997 fishing year. For Snohomish River chinook salmon, the co-managers have established a maximum exploitation rate guideline of 38% (WDFW et al. 1999), which includes all sources of mortality in all U.S. and Canadian fisheries impacting this management unit. The 1999 preseason predicted exploitation rate for Snohomish River chinook salmon was 34%4.
Based on recent ecological research, fishery managers have come to recognize the potential benefits of ecologically-based spawner escapement goals, such as those that provide adequate nutrient replenishment from salmon carcasses and, where feasible, management for escapement needs of individual sub-basins. Goals still need to be modified to provide for adequate and consistent escapements that provide for the substantive ecological benefits of salmon in the ecosystem.
Fisheries can have impacts on salmon populations in addition to the effect on escapement. In general, wild chinook salmon throughout most of the West Coast (and almost certainly including the Snohomish River, although no local historical data are available to confirm this) have gotten smaller and younger due in part to size and age selective harvest. Changing ocean conditions may also have played a role. As a result, a typical female today is smaller and deposits fewer eggs than a female would have historically. An implication of this is that today's spawning escapements result in fewer eggs deposited than comparable sized spawning escapements in the past. Smaller females are also less able to dig deep redds into larger more stable substrate. Despite reduced fishing rates, size and age selectivity of fisheries has not been adequately addressed in harvest models and may remain a potentially serious problem. The effects of size and age selectivity of fisheries are amplified by increased mortality at the egg-to-emergent fry stage due to adverse changes in hydrology (increased frequency and amplitude of floods) and river channel morphology (channels are narrower or wider and/or cut off from their historic floodplain) caused by land use and flood control activities. Future management strategies will need to address these effects.
C. ARTIFICIAL PRODUCTION Hatchery activity in the Snohomish River basin has a long history. Records of various hatchery activities, such as taking eggs and planting fish, go back over a century. These efforts involved a variety of fish, including chinook salmon. Much of the early effort would be considered misguided by today’s standards. Little was known in the early days about life histories of the various fishes, what rearing and planting strategies would likely be the most successful, and the differences between various stocks and species of salmonids. It is likely that the early efforts contributed little to later returns. However, these efforts have evolved until today the hatchery effort in the Snohomish River basin is considerable (as many as 4.5 million fish planted annually, as shown in Table 4 and Table 5), and returns back to various fisheries, the river, and the hatchery are substantial.
4 From chinook FRAM model run number 0799, 14 April 1999, available from the Northwest Indian Fisheries Commission, 6730 Martin Way E., Lacey, WA 98506 or WDFW
31 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Relative to other river systems in Puget Sound, the Snohomish River has low reliance on hatchery stocks. Management of Snohomish River chinook salmon has been keyed to the needs of wild fish and maintenance of wild production.
Although hatchery-produced salmon can partially mitigate for reduced natural productivity, they can also be detrimental to remaining wild populations. These effects have been extensively documented and debated (for example, see Schramm and Piper 1995). Busack and Currens (1995, p. 71) state that “a hazard is a potentially adverse consequence of a[n action], whereas risk is the probability of the hazard occurring.” The potential hazards posed by hatchery production to wild salmon stocks can be grouped into four principal categories:
1. Overharvest of wild fish in times and areas where they are mixed with abundant hatchery fish subject to high harvest rates;
2. Introduction of deleterious pathogens from hatchery populations into wild populations;
3. Introgression of genes from domesticated hatchery populations into wild populations due to straying of hatchery fish and potential interbreeding; and
4. Ecological and indirect genetic effects on wild populations from competition, predation, and other ecological factors (Campton 1995).
The potential straying of hatchery fish into natural spawning areas poses an additional potential hazard:
5. The masking of the true status of wild populations if managers incorrectly identify hatchery- produced fish in natural spawning areas as natural origin recruits.
Hazard 1) poses a low risk because Snohomish River chinook salmon are managed for natural production5. The entire suite of fisheries impacting Snohomish River chinook salmon are managed for the appropriate wild stock harvest rate, which is lower than the rate would be if the hatchery stock drove the fishery. Because of this, large surplus escapements are typically seen at the Wallace River hatchery.
Hazard 2) also poses a low risk in this basin. All Puget Sound hatcheries operate under the co- managers’ disease control policy (NWIFC and WDFW 1998), which has been effective in preventing the transmission of disease among watersheds. Within the Snohomish River basin, the chinook salmon at both the Tulalip and Wallace River hatcheries have been virtually disease- free since 1988, which is as far back as the disease history database goes (Bruce Stewart, Northwest Indian Fisheries Commission, personal communication 8/20/99). At both state and tribal hatcheries, pathologists are called in to investigate as soon as the first signs of disease or
5 This objective is mandated by the Puget Sound Salmon Management Plan and affirmed each year in the Stillaguamish/Snohomish status reports, which include annual fishery management plans. Stillagumish/Snohomish status reports are available from the Northwest Indian Fisheries Commission/6730 Martin Way E./Lacey, WA 98506 or from the Washington Department of Fish and Wildlife.
32 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population any abnormal fish mortalities are seen. In addition, even when fish are apparently healthy, pathologists perform disease screening of all populations of fish or eggs in a facility (Bruce Stewart, Northwest Indian Fisheries Commission, personal communication, 8/20/99).
Hazard 3) poses a potentially moderate to high risk for Snohomish River chinook salmon. For genetic transfer to occur between wild and hatchery populations, the fish must be concurrently present in natural spawning areas in spawning condition and the wild and hatchery fish must also actually interbreed.
Studies are currently underway to investigate the straying of hatchery fish into naturally spawning populations of Snohomish chinook salmon. Preliminary results (Kit Rawson, Tulalip Tribes, personal communication, 8/20/99) indicate that the contribution of hatchery-produced fish to naturally spawning populations in the Snohomish ranged from as low as 5% to greater than 60% in 1997 and 1998. Whether the wild and hatchery fish actually interbreed in these areas has not been established, but it is likely that they do. Whether interbreeding is deleterious is still a question, however, for, as Busack and Currens point out, the effect of outbreeding depression is still one of the major unanswered questions concerning the risk of hatchery programs to wild populations.
Hazard 4) presents a potentially high risk to wild Snohomish River chinook salmon populations. The levels of chinook salmon enhancement at the Wallace River hatchery may be great enough to create negative competitive interactions with wild fish under some conditions, although this question has not been investigated yet. Similarly, some programs, especially the yearling chinook salmon program, may produce fish that consume some wild chinook salmon. Again, this question has not been investigated yet.
Hazard 5) also presents a risk. The preliminary 1997 and 1998 results of the straying investigations show that the spawning escapements of natural origin recruits have been overestimated in existing databases. The likely degree of this overestimate will not be known until several more years of straying data are available.
All of the above risks are being considered in development and implementation of plans to modify chinook salmon hatchery programs in the Snohomish basin. Significant changes are being made to reduce unintended effects on genetics, distribution, and survival of native stocks. Examples include shifting production to use of local brood stock at the Wallace River hatchery and allowing fish passage and natural production above the Wallace River hatchery rack. Fishery managers are also completing an implementation plan for mass marking of hatchery chinook salmon with a readily identifiable external mark (i.e. adipose fin clip) so that hatchery and wild fish can be distinguished. The removal of large woody debris and blockage of fish at the Tokul Creek Hatchery diversion dam remains an issue.
At both the Tulalip and Wallace River hatcheries (shown in Figure 7), chinook salmon have been thermally mass-marked since the 1993 brood year. Sampling of the Tulalip terminal area fishery and of natural spawning areas for marked fish began in 1997. Analysis of these samples is providing information on the degree to which the terminal fishery can selectively harvest hatchery fish and the contribution rate of hatchery fish to different components of the natural
33 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population spawning escapement. Both of these types of information are necessary to properly implement the artificial production guidelines.
Figure 7. Major chinook salmon artificial production facilities in the Snohomish River watershed.
1. Wallace River Hatchery There has been a hatchery at the current Wallace River site near Goldbar since 1907. An earlier egg-taking station was active on Elwell Creek. The rearing capacity was expanded in 1974 with the construction of what were then spawning channels to the north of the main hatchery buildings and ponds on the peninsula of land between May Creek and the Wallace River. These narrow long channels were intended to be spawning channels for chum and chinook salmon but were later converted to rearing channels. The adult trapping facility associated with the channels was modified in the early 1980s so that it was independent of the channels. The facility was a salmon
34 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population hatchery with emphasis on coho and chinook salmon until the merger of the Washington State departments of Fisheries and Wildlife. Since then, steelhead trout (summer and winter runs) have been reared on station in addition to coho and chinook salmon.
The hatchery is operated with surface water from both May Creek and the Wallace River. The quality and quantity of this surface water is adequate for program needs most years. Occasionally the poundage of young fish on hand bumps up against the availability of water. Typically this occurs in the spring of the year when the poundage of smolts being produced results in the highest pond loading. Once or twice a decade a delay in the onset of the fall flows can also cause problems. The quality of the water is generally good with temperatures in the acceptable range. The unusual low flows of the fall of 1998 resulted in some of the highest stream temperatures seen in the last twenty years in the Snohomish County area. The river water temperatures in the late summer at the hatchery reached the upper sixties (67 to 68°F.). Holding the chinook salmon brood stock at these temperatures didn’t seem to cause major problems though the pick-off of the resulting eggs at the eye stage was a little higher than normal; 7% compared to the usual 4 to 5% (Doug Hatfield, personal communication). The main rearing problem has been fish diseases. The normal diseases associated with hatcheries have been encountered, but they have generally been controlled without impacting production. Cryptobia (a blood fluke), a persistent problem at this facility, is not usually seen at most state facilities. In recent years losses from Cryptobia have been controlled to acceptable levels.
Table 4 summarizes the hatchery production releases into the Snohomish River basin for the last 45 years. In the 1950s and 60s, these plants were from fall origin stocks after only limited rearing (age zero releases - brood year +1). These fish were primarily of what now is termed Green River fall chinook salmon stock. The sources were a variety of hatcheries including Big Soos Creek, Voights Creek, Samish River, Deschutes River and Issaquah Creek. In one case (1952), fish were brought from the Kalama River. The releases during the 1950s were generally at the hatchery site (May Creek) and averaged about a million fish per year. During the 1960s, production increased to about 2.8 million fish all of which were age zero Green River fall chinook salmon. The majority of the releases were at site although most years some of the fish were released off-site. The off-site releases were generally in the mainstem Skykomish or Snoqualmie rivers but included some releases in the smaller tributaries (North Fork Skykomish River, Elwell Creek, Sultan River, Cherry Creek, and in 1965 the Middle Fork Snoqualmie River).
During the 1970s the program at the Wallace River facility underwent further changes with the development of a summer chinook salmon program. Initially, there was difficulty getting the needed brood stock, but this was overcome when the brood stock collection was moved to the Sunset Falls trap and haul facility. The summer chinook salmon are released as yearlings (brood year + 2). With the exception of the 1976 release to the Sultan River of the fish resulting from the crossing of Skykomish River and Cowlitz River summer chinook salmon (34,861 fish) the hatchery fish have all been released on site. The fall program remained much the same as in the 1960s with the majority of the fish being released on site. In most years fall chinook salmon were brought from out of the basin for rearing at the facility. In 1974 and 1975, some of the fall fish were held for an additional year and released as yearlings. The average release for the 1970s was 2.9 million fish.
35 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Table 4. Wallace River hatchery releases of chinook salmon in the Snohomish River basin. Brood Fall Stock Releases Summer Stock Releases Total Plant Year Br Yr +1 Br Yr + 2 Br Yr + 1 Br Yr + 2 for Br Year 1952 654,000 654,000 1953 261,000 261,000 1954 576,000 576,000 1955 653,000 553,000 1956 1,500,000 1,500,000 1957 1,556,000 1,556,000 1958 1,477,000 1,477,000 1959 1,555,000 1,555,000 1960 1,796,000 1,796,000 1961 2,008,000 2,008,000 1962 3,153,000 3,153,000 1963 1,858,000 1,858,000 1964 4,443,000 4,443,000 1965 6,883,000 6,883,000 1966 2,060,000 2,080,000 1967 1,764,000 1,764,000 1968 2,818,000 2,818,000 1969 1,805,000 1,805,000 1970 3,611,000 3,611,000 1971 2,496,000 14,000 2,510,000 1972 2,034,000 188,000 42,000 2,264,000 1973 1,495,000 909,000 48,000 2,452,000 1974 2,366,000 502,000 35,000 2,903,000 1975 2,779,000 2,779,000 1976 2,125,000 903,000 3,028,000 1977 1,400,000 416,000 1,816,000 1978 3,746,000 538,000 4,384,000 1979 3,428,404 480,000 3,888,404 1980 1,135,000 2,085,000 3,220,000 1981 953,000 685,000 291,000 1,929,000 1982 1,069,000 1,087,000 149,000 2,305,000 1983 1,581,000 196,000 1,777,000 1984 1,035,000 437,000 220,000 1,692,000 1985 1,080,000 396,000 214,000 1,690,000 1986 649,000 184,000 208,000 1,041,000 1987 1,536,000 20,000 183,000 1,739,000 1988 364,000 18,000 220,000 602,000 1989 500,000 1,033,000 1,533,000 1990 2,795,000 179,000 2,974,000 1991 1,351,000 126,000 214,000 1,691,000 1992 2,580,000 189,900 405,000 254,000 3,408,000 1993 519,000 268,000 750,000 281,000 1,818,000 1994 1,204,000 280,000 278,000 1,762,000 1995 1,081,000 265,000 918,000 270,000 2,534,000 1996 1,110,000 1,120,000 2,290,000
Beginning with the 1980 brood year, a portion of the summer chinook salmon program was reared as age zero fish. The summer production has been released on site except for the 1980 brood year, when 200,000 fry were released in the North Fork Skykomish River and 300,000 in
36 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population the Skykomish River. Nearly all the fall chinook salmon released during the 1980s were from brood stock collected at the Wallace River hatchery, and they were released at site. The average release during the 1980s was 1.8 million fish with a typical plant being a little over one million. The summer stock releases were about 200,000 yearlings and the rest were planted as age zero fish.
The program during the early 1990s was much the same as the 1980s program. The most dramatic change came with the 1997 agreement between the Tulalip Tribes and WDFW to restrict egg takes to August in an attempt to eliminate Green River fall chinook salmon brood stock from the hatchery program.
2. Tulalip Hatchery Chinook salmon production by the Tulalip Tribes began with the rearing of fish to the yearling stage in the lower Tulalip Creek pond in 1973-1974. The lower pond facility was built below the small dam, constructed on Tulalip Creek between 1917 and 1919 to produce electricity and power a small sawmill. The Tulalip hatchery was expanded to include rearing ponds at Battle Creek in 1976, and the chinook salmon program was concurrently expanded. In 1981 the Tulalip hatchery began operation, and chinook salmon were received as eyed eggs to be incubated,
Table 5. Tulalip Hatchery releases of chinook salmon into Tulalip Bay. Brood Fall Stock Releases Spring Stock Releases Total Plant Year Br Yr +1 Br Yr + 2 Br Yr + 1 Br Yr + 2 for Br Year 1972 985,000 985,000 1973 831,000 831,000 1974 653,000 653,000 1975 1,996,000 500,000 2,496,000 1976 1,000,000 1,059,000 2,059,000 1977 950,000 995,000 1,945,000 1978 2,957,000 2,957,000 1979 2,001,000 343,000 2,344,000 1980 978,000 629,000 1,607,000 1981 1,577,000 1,577,000 1982 1,500,000 1,500,000 1983 560,000 560,000 1984 920,000 920,000 1985 1,530,000 1,530,000 1986 1,058,000 1,058,000 1987 1,425,000 1,425,000 1988 625,000 625,000 1989 1,400,000 1,400,000 1990 1,390,000 1,390,000 1991 1,188,000 1,188,000 1992 1,490,000 1,490,000 1993 1,280,000 35,200 1,315,200 1994 1,265,000 37,000 1,302,000 1995 1,860,000 30,497 1,890,497 1996 1,900,000 40,700 1,940,700 1997 1,700,000 1,700,000
37 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population reared, and released on reservation. All releases of chinook salmon by the Tulalip Tribes (Table 5) have been on-site into Tulalip Bay.
The fall chinook salmon program at the Tulalip hatchery has used fry or eyed eggs from WDFW facilities, primarily Wallace River and Skagit River (Clark Creek) hatcheries, along with Green River, Samish River, and Hood Canal as sources. Since the 1990 brood year the Wallace River hatchery has been the sole provider of fall chinook salmon eyed eggs to the Tulalip hatchery. In 1997, the co-managers agreed to terminate fall chinook salmon releases at Wallace River hatchery (WDFW-Tulalip Memorandum of Understanding, August 26, 1997). As a result of this decision, it may be necessary to seek an alternative source of fall chinook salmon eggs for the Tulalip hatchery chinook salmon program or to investigate the feasibility of developing a summer chinook salmon program at this facility. Both of these options are currently being pursued.
As a result of many years’ discussions between the Tulalip Tribes and the WDFW, a spring chinook salmon program was initiated at the Tulalip hatchery beginning with the 1993 brood year. The principal objective of this program is to provide early-returning chinook salmon for the first salmon ceremonies conducted by tribal members. This program uses eyed eggs from hatchery spring chinook salmon returning to the Skagit River facility. Approximately 35,000 yearlings per year have been released, all of which are marked with coded-wire tags.
D. HYDROPOWER PROJECTS Two types of hydroelectric operations are present in the Snohomish River basin: storage facilities and run-of-the-river facilities. The Henry M. Jackson and the South Fork Tolt River hydroelectric projects are both storage facilities. The remaining projects in the Snohomish basin are all run-of-the-river operations with very limited or no storage.
Unnatural fluctuations in stream flow occur downstream of hydroelectric facilities, depending on how the facility is designed and operated. Both storage and run-of-the-river operations may alter natural flow regimes on a daily or hourly basis. Daily and hourly fluctuations in flow can occur downstream of dams during peaking operations or during other changes in operation. Storage facilities, depending on the reservoir size, have the ability to alter the seasonal flow regime. Seasonal flow fluctuations tend to be dampened, with water stored during periods of high flow in the winter or spring and released in the summer when natural flows are lower. Water-level fluctuations associated with hydropower operations may reduce habitat availability, de-water spawning areas, restrict access or strand fish, or affect the migratory behavior of juvenile salmonids. Instream flow schedules, minimum flow requirements and down-ramping prescriptions are operational means of protecting the aquatic resources downstream of hydroelectric facilities.
Hydroelectric dams may also modify sediment transport, natural temperature regimes, and the concentration of dissolved gases. Water storage at dams may prevent flushing flows that are needed to scour fine sediments from spawning substrate and may disrupt the natural recruitment of gravel, wood, and other materials. The reduction in sediments downstream of dams may lead to changes in channel morphology.
38 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
1. Henry M. Jackson Hydroelectric Project The Jackson Project, formally called the Sultan River Project, was constructed in two phases. The first phase was completed in 1965 and consisted of Culmback Dam (located at RM 16.5), which impounds a reservoir, Spada Lake (Figure 8). Phase II was completed in 1984 and consists of an enlarged dam, an eight mile power conduit to the powerhouse (located adjacent to the Sultan River at RM 4.5), a pipeline to Lake Chaplain (source of municipal water for City of Everett), and a tunnel/pipeline from Lake Chaplain to a diversion dam at RM 9.7. The present diversion dam was constructed in 1929 to improve Everett’s water supply system. The tunnel/pipeline from Lake Chaplain to the diversion dam provides return flow to the Sultan River to meet instream flow requirements.
Culmback Dam is operated according to rules based on Spada Lake water surface elevations. These rules determine when and how much water is withdrawn from the reservoir. The instream flow schedule was established through an agreement with the WDFW, U.S. Fish and Wildlife Service, NMFS and Tulalip Tribes. Those agencies and the Corps of Engineers have approved the project’s operating plan, which includes powerhouse down-ramping rates.
Escapement of Sultan River fall chinook salmon and pink salmon has been monitored since 1978 and 1971, respectively. Winter-run steelhead trout have been monitored since 1979. The data show a significant increase in pink salmon escapement after 1983 (Phase II on line), while the increase between pre and post-1987 chinook salmon escapements may or may not be significant. Data for winter-run steelhead trout is sparse and inconsistent and, hence, it is difficult to analyze for trends or comparisons for this species. However, about 30,000 juvenile steelhead trout are released annually in the Sultan River below the diversion dam as further mitigation.
Two ongoing operational issues for the project are: 1) quantity and quality of bedload transport and 2) down-ramping rates at the diversion dam (the rate of decrease of river water levels due to project operation).
2. South Fork Tolt River Hydroelectric Project In 1963, the City of Seattle constructed a dam and reservoir on the South Fork Tolt River at RM 7.8 for municipal and industrial water supply. The project currently supplies 30% of Seattle’s water needs. The amount of water diverted into the supply system has gradually increased since the reservoir was put into operation. Current operating policy limits the maximum reservoir drawdown because of excessive turbidity in the water when its surface elevation drops below 1718 feet. Construction of the Tolt River filtration plant will allow lower reservoir drawdowns in the future. Current operating procedures provide some storage for incidental control of floods during the fall and winter months. However, formal flood control regulation is not possible because of drawdown restrictions.
Anadromous fish usage of the South Fork Tolt River includes winter steelhead trout and chinook and coho salmon (predominantly in the reach up to RM 1.6) and summer steelhead trout (up to a natural barrier at RM 6.8). Thus, the project is located above upstream migration of anadromous fish. Redd surveys are conducted by WDFW (for steelhead trout) and the Tulalip Tribes (for coho and chinook salmon).
39 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Figure 8. Major dams and hydropower projects in the Snohomish River watershed.
In 1979, the City applied to the Federal Energy Regulatory Commission (FERC) for a preliminary permit for hydropower development at the existing dam and reservoir. Federal, tribal and state agencies intervened in the preliminary permit proceeding, requesting that the City undertake studies to identify all project impacts and develop necessary mitigation measures prior to application for license. Accordingly, the City conducted fisheries resource studies on the Tolt River system to identify limiting factors to fish production. The University of Washington Fisheries Research Institute conducted the “Tolt River Fisheries and Instream Flow Analysis,” which investigated the basic biological and physical characteristics of the Tolt River system. An instream flow analysis of salmonid habitat requirements was conducted using the Instream Flow Incremental Methodology, including an evaluation of the potential impact on instream flows following development of the project. Negotiations following the study led to a settlement agreement in 1988, and the hydroelectric project went on line in 1995.
40 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
The Settlement Agreement commits the City to provide instream and minimum flows for steelhead trout, the predominant species in the South Fork Tolt River. Chinook salmon do not use the river extensively because it descends at a steep gradient (2.8%) over a substrate composed mainly of boulders and cobbles. The high gradient limits fish access to the upper portions of the river. Over 90% of the observed portions of the stream are classed as rapids, with the remaining 10% about equally divided between steep chutes and well-defined pools. Suitable salmonid spawning gravel is limited to pool tails and small pockets behind large boulders. Because of the steepness, rapids and limited pool tails, the South Fork Tolt River contains very little prime salmonid spawning habitat. Spawning surveys indicate that the lower 1.6 miles provide the most suitable spawning habitat. The Settlement Agreement also provides measures and commitments by the City for protection, mitigation and restoration of the South Fork Tolt River anadromous fishery.
The intervening agencies reviewed the project in light of the Washington Department of Fisheries Snohomish River Basin Guidelines (now referred to as Hydroelectric Assessment Guidelines). The City has also conducted studies to determine whether the South Fork Tolt River has a significant depletion of spawning gravel and whether additional rearing habitat can be provided through restoration of existing habitat or creation of new habitat. An Erosion and Sediment Control Plan was completed in compliance with the Hydroelectric Assessment Guidelines. The Settlement Agreement fulfills all the City's fisheries mitigation obligations for anticipated impacts during the term of the Settlement Agreement for both the project and the existing municipal and industrial water supply project, including a future water filtration facility.
3. Other Projects Five other hydropower projects are in operation in the Snohomish River basin. They are run-of- the-river type, which means that their operating plan or schedule is governed by natural river flows. They do not have reservoirs with storage capacity to provide operating flexibility. Thus, minimum instream flow requirements are not an issue with these projects. The Woods Creek project is located on a tributary to the Skykomish River. The Snoqualmie Falls project is located on the mainstem Snoqualmie River. Since both projects are sited at natural barriers to upstream fish migration, adult/juvenile safe passage past them is not an issue. The other projects are also upstream of chinook salmon migration.
A few other hydropower projects have been proposed or are in the planning and permit phase. However, because of the ESA listing for chinook salmon and the presumed pending ESA listing for bull trout, any future hydropower projects will have to address their potential adverse effects on these species as well as others.
E. FRESHWATER AND ESTUARINE HABITAT Important human land uses in the Snohomish River basin include forestry; urban, industrial, and residential development; infrastructure, recreation, agriculture and mining. These activities have altered much of the habitat used by salmon and disrupted the natural processes that maintain it, although some quality habitat areas remain. This section discusses the human impacts on chinook salmon habitat and identifies the high priority habitat problems in the basin.
41 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
1. Human Populations and Land Use The floodplains and rivers of the Snohomish River basin have been occupied and used by non- native Americans for more than one hundred years. Records from the late 1800s show that woody debris was removed from the rivers to improve navigation and significant quantities of salmon were harvested. Beginning in 1890, the mainstem rivers were used for moving logs and crops to Port Gardner, and maps from 1921 show agricultural development on the floodplains and growth of cities in the Snoqualmie and Snohomish river valleys. Aerial photographs taken of the estuary area during the 1950s reveal significantly more log rafting and riverside processing than occurs today (Pentec 1998).
Private, state and federal forest lands and wilderness areas cover 74% of the basin area. The Mount Baker-Snoqualmie National Forest occupies a large portion of the upper watershed. Federal forest land in the basin is primarily managed by the United States Forest Service (USFS) under the National Forest Management Act and the Northwest Forest Plan. State and private forests are managed under the State Department of Natural Resources. The Alpine Lakes and Henry M. Jackson Wilderness Areas are highly protected, and land use activities that could be considered detrimental to salmonid habitat are minimal. Other areas are designated as habitat for late-successional and old-growth related species, where timber harvest is restricted to activities with specific restoration or conservation objectives. Timber harvest, road building, and other management activities are also restricted in areas along streams, wetlands, ponds, lakes, and potentially unstable areas to protect the health of the aquatic system and its dependent species, including salmonids. Most timber harvest occurs outside these special areas.
Agricultural lands dominate the flat floodplains of the Snoqualmie and Snohomish rivers and account for about 5% of the basin area. In addition to commercial agriculture, there are a significant number of small farms in these basins. Rural residential development is scattered throughout the floodplains and surrounding uplands. Urban lands are concentrated in Everett and Marysville at the mouth of the basin and in small cities located along the rivers up to the Cascade Mountains.
Population in the basin is projected to increase by 53% from 206,000 in 1995 to 315,000 in 2020 (Pentec 1998). Sub-basins with zoning potential for more than 10% impervious surface are at risk for urbanization effects (Pentec 1998). Habitat resources in the Snohomish River basin are not only impacted by urbanization within the basin, but also by increased demand for water by growing populations within and outside the basin. According to the Puget Sound Regional Council (1992) and information from water supply plans, the population served by the Snohomish River basin will increase from 965,000 to 1,389,000 by the year 2020. Applying a per capita usage of 125 gallons per day, this population growth translates into a 53 million gallons per day increase in total water demand (Pentec 1998).
Gravel has historically been removed from some rivers in the basin to offset losses in channel capacity due to diking and for commercial purposes. For example, gravel was dredged regularly from the Raging and Tolt rivers until large-scale removal was halted in the late 1960s. Gravel bars were scalped in the South Fork Snoqualmie River in the early 1990s in response to flood events in North Bend. Dredging is still done in the lower estuary to maintain navigation channels.
42 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Figure 9. Land use in the Snohomish River watershed.
Roads and railroads are built along many of the rivers, influencing movement of water and the location and shape of the rivers. Although the area dedicated to infrastructure (e.g. roads, rail lines, utility crossings, and bridges) is not quantified, the effects are pervasive and long-lasting. These include channel straightening, bank armoring, placement of piers in channels, and non- point pollution from road-related runoff. Normal and emergency maintenance and repair activities can exacerbate problems associated with such structures. Normal problems include removal of large woody debris, placement of rip-rap, localized scour (with concomitant deposition in other areas), and water quality problems. Emergency infrastructure repairs, particularly along railroad rights-of way, can lead to long-term, chronic problems.
43 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Types of land use, potential densities, and likely impacts on chinook salmon habitat vary greatly across the watershed (Figure 9). Current and future land uses, and key issues for the future are summarized below for each sub-basin (refer to Figure 4 for the sub-basin boundaries).
(1) Snohomish River Estuary and Nearshore Areas
This 154 square mile area includes the Snohomish River estuary and the nearby coastal drainages. It is the most densely populated portion of the Snohomish River basin, containing 57% of the population in just over 8% of the land area.
It is also the most heavily urbanized sub-basin. Comprehensive planning policies strive to locate future growth in designated Urban Growth Areas (UGA). Forty percent of this sub-basin is designated as UGA, accounting for 57% of the total designated Urban Growth Area in the entire Snohomish River basin. In other words, more than half of the future growth in this watershed will be concentrated around the estuary and nearshore drainages.
Major land uses include urban, residential, agriculture, transportation and commercial/industrial. A few small forest areas remain, mostly on the Tulalip Indian Reservation. The City of Marysville and the majority of the cities of Everett and Snohomish are located in this sub-basin. The chinook salmon habitat problems associated with past and current land uses include hydromodification (levees, dikes, bank revetment/stabilization, bulkheads, groins, etc.); clearing of riparian forests, scrub-shrub wetlands and forested wetlands; construction of roads, bridges and other public works; and floodplain development for industrial, commercial and urban uses. Shoreline alterations due to installation of rip-rap, industrial development, shipping, and the naval station have displaced key saltwater habitat. Dredging in the lower river and Port Gardner also disrupts nearshore habitat.
In the estuary, diking has isolated large areas of former salt and tidal freshwater marshes from the river. These complex marsh, mudflat, and channel habitats are important rearing and saltwater adaptation areas for juvenile salmonids (Simenstad et al. 1982, Healey 1982). Loss of estuarine habitat reached its maximum in about 1970. In the last decade, natural and intentional breaching of dikes has allowed re-establishment of tidal influence over several hundred acres. The Spencer Island marsh is an excellent example of wetland values that develop when dikes are removed.
(2) Snohomish River Mainstem
The Snohomish River mainstem sub-basin includes the Pilchuck River and other lower tributaries that empty into the Snohomish River below the confluence of the Snoqualmie and Skykomish rivers. It encompasses a total area of 178 square miles, or roughly 10% of the Snohomish River basin, and provides homes for 18% of the basin’s human population.
The majority of the land is designated for rural residential uses in Snohomish County’s Growth Management Act comprehensive plan. Approximately 20% of the basin is forested, mostly along the upper tributaries of the Pilchuck River. The City of Lake Stevens is in this sub-basin, along with parts of the cities of Monroe, Granite Falls, and Snohomish. The combined UGA of these cities covers 16 square miles (9% of the sub-basin).
44 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Agriculture is another significant land use in this area, especially near French Creek and along the Snohomish River mainstem. The combination of levees and riparian clearing for agricultural activities has removed most of the mature forest along the mainstem and French Creek. There are several pump stations associated with the dikes, including two large ones. The only one with fish passage is at French Creek. The rivers do not interact with the riparian area except when flood flows spill over the top of the dikes.
(3) Skykomish River Mainstem
Moving further upstream, urban and residential development decreases and forestry increases. The Skykomish River mainstem and its tributaries (below the two major forks) drain 325 square miles, more than three-quarters of which are forested hills and mountains.
The most common land use outside the forests is residential, with particular concentrations in the lowlands near the cities and in the hills that form the western border of the sub-basin. The cities of Gold Bar and Sultan, and part of the City of Monroe, are located along the northern bank of the river. A major transportation corridor (Highway 2) parallels the river. The UGA boundaries have a combined area of eight square miles. The population of this area is close to 20,000, or 8% of the total Snohomish River basin’s human population.
Outside the cities, the floodplain primarily supports agricultural uses. Levees, roads, railroads and riparian clearing have isolated the Skykomish River from the floodplain and riparian forests along most of its length.
(4) Skykomish River Forks
Above the mainstem, the North Fork Skykomish and the South Fork Skykomish rivers drain 507 square miles, 98% of which are forested. Low density residential development and transportation along the valley floors make up most of the rest of the land uses. Less than 1% of the Snohomish River basin population is found along the Skykomish River forks. The cities of Index and Skykomish, with a combined urban growth area of only one-half square mile, are the only urban centers. There is very little commercial, industrial or agricultural activity in this sub- basin.
Timber harvest has had significant impacts in this area. Logging road failures, especially in the Beckler and Tye river drainages, have resulted in channel destabilization and accelerated delivery of fine sediment. This can cause channel aggradation, reducing pool depths and quality of pool and spawning habitat.
(5) Snoqualmie River
The Snoqualmie River watershed comprises 692 square miles. Predominant land uses are forestry and agriculture, with more than 75% of the basin's land area in a County-designated Forest Production District. There are four incorporated cities (North Bend, Snoqualmie, Carnation, and Duvall) and two unincorporated towns (Preston and Fall City), with extensive
45 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population transportation infrastructure in the valley. Much of the future growth in the Snoqualmie River watershed is anticipated to occur within these cities and towns.
Many of the major tributaries to the Snoqualmie River draining from the east side of the basin have their headwaters in predominantly forest land use. The future health of these watersheds will be dependent on achieving King County Comprehensive Plan goals for retaining lands in low density forest use; minimizing impervious surface; addressing existing problems with road failures and blockages to fish passage; and carrying out sound forest harvest practices. Watershed analyses with forest management prescriptions have been completed for the Tolt River and Griffin and Tokul creek basins.
Another major land use issue in the Snoqualmie River watershed is the potential for high-density development outside the urban growth boundary on lots that were legally in existence at the time the Comprehensive Plan was adopted. Land clearing and creation of new impervious surfaces could reach thresholds where significant changes in hydrology, channel stability, and water temperature occur. Key sub-basins of concern include: Cherry Creek and Harris Creek on the east side, and Ames Creek, Patterson Creek, Tuck Creek, and other small tributaries draining from the west side of the Snoqualmie River watershed.
In general, the goal of retaining low density, agricultural use of the 100-year floodplain is seen as compatible with the goal of protecting key habitat functions. However, livestock access to stream banks, manure management, maintenance standards for watercourses and drainage ditches, and the lack of vegetation along river corridors raise concerns in some areas. A key challenge will be protecting critical habitat functions while supporting agriculture as a desired land use. King County policies limiting conversion from agriculture to other uses might limit the use of conservation easements and land acquisitions intended to protect spawning and rearing habitat.
Although Snoqualmie Falls is a natural barrier to anadromous fish passage, land use and development practices above Snoqualmie Falls can still affect physical, chemical, and biological processes that shape habitat in the basin as a whole. Key population and land use issues above Snoqualmie Falls include clearing and development in headwater areas, development and fill in the floodplain, forest practices, and maintenance of levees and revetments.
2. Interaction of Human Populations, Land Use and Habitat Conditions Human activities impair salmon habitat directly by altering physical, biological and chemical conditions. Some activities also disrupt the natural processes that would otherwise create and maintain salmon habitat. Bank stabilization and removal of large woody debris from streams are examples of direct alterations. Process changes include, for example, increased frequency and volume of flood flows resulting from increased impervious surface in watersheds.
Physical changes to the basin include bank stabilization; diking; placing roads, levees and revetments in areas that cut off side channel habitat and restrict channel migration; filling and developing the floodplain and wetlands; dredging; gravel mining; riparian forest removal; woody debris removal; construction of fish passage barriers and impervious surfaces; water withdrawals and log raft storage. These and other anthropogenic impacts continue to simplify and disrupt the
46 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population ecological conditions that allowed chinook salmon to evolve a variety of survival options and adaptations. The historic regime of periodic natural disturbances producing a mosaic of floodplain habitat conditions has been abruptly replaced. In its place is a regime in which chronic disturbances repeatedly assault a restricted range of riverine habitat conditions, leaving chinook salmon with few refuges and alternatives. This section describes some of the major ways land use and human activities can damage salmon habitat. a) Bank Hardening, Diking and Dredging
The erection of levees and dikes in the early part of this century disconnected floodplain refuge and habitat from the lower mainstem Snohomish River and estuary, resulting in a loss of over 70% of salmonid rearing habitat in that area. Rip-rapping, diking and dredging continue to confine river channels to their present courses and prevent water from flowing over the floodplain. Where the intent is to moderate or reduce the severity of flooding, the result is to disconnect the river from its floodplain and disrupt natural processes.
Fine sediments eroded from upstream reaches cannot be spread out onto the floodplains. This deprives the floodplain of soil-building materials and nutrients and disrupts terrace-building. The fine sediments remain in the main channel and settle out, covering and clogging spawning gravel.
Where flood flows cannot erode the floodplain surface, channel migration is eliminated. Physical processes that maintain healthy riparian plant communities and properly functioning off- channel habitat are impaired or completely prevented. This decreases the diversity of healthy riparian plant species on the floodplain. In turn, it limits the exchange of nutrients between land and water, reducing the productivity of the aquatic environment.
Bank hardening and construction of dikes and levees also restrict natural river processes that form gravel bars, side channels, and sloughs necessary for successful salmon spawning and rearing. Complex off-channel habitat such as back-channels and springbrooks are no longer created and existing ones begin to fill in with fine sediment and accumulated organic matter, reducing the availability and quality of salmon rearing habitat.
Channel confinement also increases the velocity of peak flows through the active channel, reducing the opportunity for high flows to infiltrate hyporheic interstitial spaces and recharge the hyporheic zone of the floodplain with cold water. In addition, this reduces the ability of the river to exchange nutrients with riparian soils via the hyporheic zone. Accumulated fine sediment and organic matter in off-channel habitat further reduces interactions between the stream and the underlying groundwater.
By limiting flooding and channel migration, diking and dredging prevent the river from recruiting large woody debris to the channel and channel banks. Over decades, this impairs the processes that support normal patterns of vegetational succession on the floodplain, further diminishing the health and species complexity of the riparian zone.
47 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
Dredging the channel has the further consequence of lowering the water table by dropping the level of the active channel during low flow below its historic level relative to the floodplain. This reduces riparian and floodplain wetland health and species diversity and further impairs the ability of high flows to recharge the hyporheic zone. This has major impacts on stream temperatures and on temperatures in the riparian zone during normal summer low flow periods. Temperatures in both environments become warmer and more homogeneous. b) Fish Passage Barriers
Numerous tributaries within the floodplains of the Snoqualmie and lower Snohomish rivers have access problems preventing salmonid use. Impassable culverts and barrier gates have restricted fish access to suitable rearing and spawning habitat. For example, pump stations on French Creek and Marshland prevent passage of juveniles upstream. In addition, culverts that were designed for fish passage were generally focused on adult passage. Only recently has the issue of juvenile salmonid passage upstream through culverts been recognized as an important factor that could restrict carrying capacity (WDFW 1997a,b). The use of tributary habitat by over-wintering juvenile coho and chinook salmon can be significant (CDF&G 1995), and the lack of access to such habitat within the Snohomish River watershed is widespread.
Flood protection has also required installation of flood or tide gates in the dikes, limiting fish access to and from many valley bottom tributaries that provide important summer rearing and winter refuge for juvenile salmon. c) Increase in Effective Impervious Surface Area
Effective impervious areas have reduced infiltration characteristics compared to undisturbed forest or other native ecosystems, resulting in increased surface runoff. In order of increasing magnitude, the following land uses have effective impervious area:
• Managed forest (skid roads/trails, etc.);
• Pasture, lawn and crop land;
• Low to medium density residential development, business parks and schools;
• High density residential, commercial and industrial development; and
• Shopping centers and roads.
According to Horner and May (1998), about 60% of effective impervious area is related to transportation. Providing infiltration on-site (i.e., preventing runoff from the site) decreases the effective impervious area.
Urbanization in the middle and lower watershed is altering hydrologic conditions by creating substantial areas of impervious surfaces. An estimated increase in impervious surface area to 10% is all that is needed for measurable alterations to channel morphology and basin hydrology
48 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
(Booth and Jackson 1997). This makes rivers flashier and more prone to larger and more frequent flooding. It also causes stream channels to erode vertically, further disconnecting them from their floodplains and lowering local water tables.
The creation of impervious surfaces permanently reduces summer flows by reducing recharge to groundwater. Reductions in summer low flows affect salmon production by constricting the amount of available rearing habitat, increasing inter- and intra-species competition and allowing stream temperatures to increase above normal preference and tolerance ranges. Streams and rivers become shallower, warmer and biologically poorer. Tributary streams thus impacted by impervious surfaces contribute to a general warming of mainstem rivers during summer and early fall base flow conditions, further reducing the biological integrity of mainstem habitat for juvenile rearing and adult holding prior to spawning. Reductions in low flows may restrict access to side channels, spawning areas and other habitat. Reductions in summer low flows also increase the vulnerability of salmonid juveniles to avian predation and of adult salmon to poaching. This is especially problematic for summer-run chinook salmon that concentrate in the deeper pool habitat. d) Water Use
Two large municipal water supply systems, more than fifteen local water suppliers, and an uncounted number of domestic wells draw their water from this basin, which reduces low flows in some places. Low flows in Quilceda and Allen Creeks have diminished due to past development, and small streams such as Dubuque, Star, Patterson, Tuck, and Cherry Creeks and the Raging River are at risk for summer low flow reduction due to future development. Current in-stream flow requirements set by the Washington State Department of Ecology for August and September exceed the 7-day low flow in more than half the years with recorded flows. Population growth will increase water demand by residential, as well as commercial and industrial users.
All of the water exported from the basin comes from the Sultan and Tolt River reservoir systems. These systems store spring flows and release water in the summer, so the current reduction in summer flows in the Sultan and Tolt Rivers is rendered imperceptible or is enhanced by reservoir operations. Within-basin consumptive use in the summer accounts for about 12% of summer flow in the Snoqualmie River, 7% in the Skykomish River and 7% in the Snohomish River. These estimates do not account for small streams however, so the combined effects of residential development and associated well withdrawals may have significant impacts on low flows in small streams.
In rural areas, residential development is supported by local well withdrawals, which can have significant impacts on flows in small streams (Pentec 1998). Groundwater withdrawals anywhere within the Snohomish River basin may affect stream flows based on hydraulic continuity (Turney et al. 1995). Hydraulic continuity refers to the hydraulic connection and dynamic interactions between groundwater and surface water. An aquifer is in hydraulic continuity with lakes, streams, or other surface water bodies whenever it is discharging to, or being recharged by surface water. Pumping from wells can reduce discharge to springs and streams by capturing groundwater that would otherwise have discharged naturally to those
49 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population surface waters. If a well is close enough to a stream, pumping may even induce withdrawal from surface water that may be drawn directly to the well. Consumptive use (that portion not returned to the aquifer) eventually diminishes stream flow, both seasonally and as average annual recharge.
According to Turney, “The trend of increasing residential development and construction of central storm sewers will most likely result in decreased recharge. This combined with additional withdrawals would result in a loss of storage (with attendant decline in water levels) or a decrease in discharge to springs, rivers, or lakes, or a decrease in groundwater flow out of the basin.” In some cases it may take many years for the effects of additional groundwater withdrawals to become apparent.
Turney also makes references to small domestic wells that are exempt from the requirement to obtain a water right permit. Currently, the number of exempt wells in the basin is estimated to be quite large (several thousand) and the amount of water withdrawn by these wells is unknown. Thus, the effect exempt wells have on stream flows is unknown, essentially unregulated, and potentially very significant.
While some fish stocks of the Snohomish River basin may already be limited by low flow conditions in the summer, further water withdrawals would exacerbate productivity problems in such systems. Fisheries research has shown that productivity of coho salmon tends to be higher in years with relatively high summer flows and lower in years with relatively low summer flows in smaller tributaries to the mainstem rivers (Smoker 1953, Neave 1948 and 1949, as reported in Pentec 1998). Flow-limiting conditions occur frequently in this basin during the dry months of August and September because groundwater often cannot provide enough water to fill the wide channels created by large winter flows. Spawning available to chinook and pink salmon in mainstem reaches may also be flow-limited during these periods. e) Forestry and Agriculture
Forestry, agriculture, and flood control practices have eliminated or diminished the riparian corridor along the lower and middle Snohomish River. These practices have reduced the quality and quantity of large wood available to recruit to the channel. What remains is mainly immature deciduous forest (red alder, black cottonwood, big-leaf maple). The loss of mature coniferous riparian forests, coupled with early wood removal from the river to aid navigation, has led to the present lack of large woody debris in stream channels. Large wood in stream channels forms pools and traps spawning gravel, thus creating critical fish habitat. Generally only large wood (greater than 20 inches in diameter) is capable of forming pools in the larger rivers, although smaller pieces can function to form pools in smaller tributaries.
Removal of trees and understory vegetation exposes fine topsoil to erosion from rain, wind and slope failures. The typical result is increased frequency and intensity of storm water runoff and increased fine sediment inputs to streams and rivers. Such impacts in the upper watershed are delivered downstream as increases in peak-flow frequency and amplitude. Flood flows result in redd scour, excessive turbidity, erosion of the riparian zone, decreased longevity of in-channel wood, and sediment transport that eventually reaches the estuary. Impacts from activities such as
50 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population logging, farming, and diking are exacerbated under hydrologic conditions that further favor erosion and loss of in-channel hydraulic control.
Local channel scouring increases and more fine particles, including the smaller components of bedload such as gravel and cobbles, are transported downstream. At the same time, the depth of pools is reduced as they fill in with the excess sediments. Stream levels during the summer are often lower and stream temperatures higher. These sedimentation and temperature effects are further exacerbated by the lack of large woody debris recruitment, which results from the removal of mature trees from the riparian zone.
Much of the increase in finer suspended sediments is transported downstream during high flows to lower gradient valley floor and floodplain reaches where it settles out among the gravel and cobbles in salmon spawning areas. This reduces the overall area and the quality of available spawning gravel, thereby reducing the survival rate of fertilized eggs.
Increased percentages of fine silt and clay sediments in the active channel of mainstem floodplain rivers reduce the permeability of the channel bed and banks, which impairs the exchange of surface and hyporheic groundwater. This interrupts important biogeochemical interactions, lowering the overall productivity and complexity of aquatic and riparian food webs.
In-channel habitat has also been degraded by agricultural practices, including allowing cattle unrestricted access in riparian zones of the mainstem sub-basins and their tributaries. This problem is especially prevalent along the Snoqualmie and lower Snohomish rivers, where the loss of riparian vegetation from such practices also contributes to bank instability that generates further erosion and fine sediment delivery to the system. In addition to the direct effects on riparian and in-channel habitat caused by unrestricted livestock, this practice is likely the principal cause of fecal coliform and ammonia levels which exceed standards for much of the mainstem Snoqualmie and Snohomish river systems (Washington Dept. of Ecology 1997). f) Water Quality
The Snohomish River serves as a conduit for organic enrichment to the estuarine and nearshore environments. This habitat is critical for the rearing of out-migrant salmonid smolts – especially chinook, chum and pink salmon. The basin is currently recovering from some historic impacts. For example, contaminant contributions have decreased in the estuarine zone, where industrial activity has declined and municipal sewage treatment has improved in recent decades.
Nitrogen and phosphorus liberated from organic carbon and sorbed particulates ultimately control the primary and secondary production of the waters in the lower river and estuary. The natural balance of nutrient inputs has been exceeded and the timing and form of the inputs has been modified, primarily by agricultural practices, urban development and forestry activities.
Water quality problems that can affect fish production in the Snohomish River basin include low dissolved oxygen, high water temperature, and chronic turbidity (Washington Dept. of Ecology 1997). Water quality in the basin is generally good except in specific locations like Marshlands, French, Quilceda, Allen and lower Patterson creeks. Dissolved oxygen has been especially
51 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population affected by unfiltered agricultural runoff that increases biological oxygen demand. Elevated water temperatures occur in river and stream reaches as a result of insufficient riparian canopy, resulting in lack of shading. Low flows can also contribute to elevated water temperatures. Stormwater runoff from urban, agricultural, and forested lands has contributed suspended and dissolved solids that increase turbidity.
3. Factors Contributing to Decline The Technical Committee identified several factors as leading causes for the degradation of habitat in the Snohomish River basin and the resulting decline in chinook salmon productivity. Then they ranked the relative importance of these problems for the quality and quantity of freshwater and estuarine salmonid habitat. Distinguishing the importance of each factor in relation to numerous others is somewhat difficult because many of the factors are the result of changes that affect different watershed processes at different locations and during different times. For example, log jam removal that took place nearly one hundred years ago (for navigation and flood control) and the contemporary lack of mature riparian forests are both responsible for the chronic absence of large, pool-forming woody debris in the mainstem Snohomish River. Past land clearing removed nearly all large historic wood, while riparian harvesting has reduced the overall size of trees that might otherwise fall into the river.
The relative ranking of the significance of a habitat factor by one committee member may differ from that of another, which reflects the individuality of experience and local knowledge. These rankings are not meant to be absolutes. They merely reflect a sense of the mix of factors contributing to the general decline in habitat suitability to provide essential life history requirements for salmonids within the basin.
Most of the factors ranked below reflect the outcome of alterations to processes controlling these major components of the system itself. The long-term solution to habitat problems depends on our ability to reestablish processes that create and sustain habitat, such as flow regimes and inputs of sediments and large woody debris. a) Evaluation Process
The Technical Committee listed 34 problem statements (Appendix B) and established a set of criteria for evaluating them. The problem statements are a combination of problems identified by members of the Technical Committee and problems frequently mentioned as potential causes of salmonid stock decline. The criteria were designed to identify issues that have the greatest impact on habitat productivity in the freshwater and nearshore environment of the Snohomish River basin. The ranking criteria included:
1. How the problem may limit chinook salmon productivity in the basin through:
• Loss of rearing habitat quality or quantity; • Decreased egg to emergent survival; • Acute juvenile mortality; and/or • Adult mortality.
52 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
2. Scale of factor – a measure of the prevalence of the problem basin-wide.
3. Severity of factor – how serious are the consequences of the problem?
4. Trend – an estimation of whether the problem is getting worse, getting better, or stable.
Using their firsthand knowledge of the basin and best professional judgment, Technical Committee members evaluated the problem statements against the criteria listed above. b) Results
Eleven Technical Committee members participated in the evaluation. They identified nine high priority problems. Each was a high or medium factor that limits productivity, and each raised concerns in at least one of the other criteria categories. Responses for the first four problem statements in the following list consistently fell into categories that signal probable cause for concern (Appendix C summarizes the evaluations for these nine problem statements).
1. Loss of channel area and complexity due to bank protection and diking of the river and major tributaries, cutting off the channel from its floodplain.
2. Dearth of in-channel large woody debris.
3. Flood flows that scour redds at high frequencies.
4. Increased sediment input to streams as a result of slope failures.
5. Poor quality riparian forests.
6. Loss of wetlands due to draining for land conversion that eliminates habitat and reduces water retention.
7. In redd mortality due to siltation or water quality contamination.
8. Urbanization (road construction, commercial and residential construction, additional bank hardening) that further reduces chinook salmon viability in the basin.
9. Artificial barriers (dams, tide gates, diversions, culverts, pump stations) that prevent juveniles from reaching rearing habitat. c) Conclusions
The results of this exercise should be used to guide early actions to protect chinook salmon. Activities undertaken to improve our understanding of the highest priority problem statements, as presented above, will provide critical support to the long-term recovery plan. If local jurisdictions want to move forward with early actions to facilitate chinook salmon recovery, those actions should be designed to address the highest priority issues, particularly any of the first four problem statements included in the list above.
53 Initial Snohomish River Basin Chinook Salmon Chapter V Conservation/Recovery Technical Work Plan Factors Affecting the Population
The process described above has some obvious limitations resulting from the short time frame established for releasing a preliminary report on chinook salmon recovery and conservation in the basin. Presently, the Snohomish River basin has not been the subject of a basin-wide limiting factors analysis or a historic reconstruction of salmonid stocks and habitat. The criteria used for evaluation purposes were established by consensus of the technical staff assembled for this effort, based on existing research and best professional judgment.
4. Remaining Critical Habitat and Linkages a) Introduction
Recovery of threatened populations has the greatest probability of success when recovery initiatives build upon remaining critical habitat conditions and processes within the geographic range of the target populations (Doppelt et al. 1993). Preservation of remaining habitat and processes is therefore critical to successful recovery efforts and is accorded a high priority by the Technical Committee. In addition, preservation is typically more cost-effective by orders of magnitude in comparison to the large-scale habitat restoration actions that may also be necessary to achieve recovery of chinook salmon (National Research Council 1996).
This section includes a preliminary list of principal habitat areas and related processes in the Snohomish River basin that should be targeted for preservation actions. Two general points need to be made at the start:
• The list is very general and lacks specific citations of land ownership. The current information base used to create the list of critical habitat will need to be supplemented in the coming months by the use of recent aerial photographs, GIS mapping, and on-ground site evaluation.
• The list does not address the need to systematically prioritize habitat preservation opportunities. An ecosystem framework such as the "Ecosystem Diagnosis and Treatment (EDT)" methodology developed by Mobrand Biometrics may help with these decisions. b) Categories of Critical Habitat
Due to the complicated and somewhat unique relationship between the populations of chinook salmon in the basin and their remaining critical habitat, it is useful to recognize three kinds of habitat that merit preservation:
1. Habitat which chinook salmon require and currently use during key freshwater/estuarine life stages, such as spawning and juvenile rearing and over-wintering.
2. Habitat normally inaccessible to chinook or having limited use but physically and/or hydrologically connected to the reaches which chinook salmon actually use which maintain normal habitat conditions and processes related to temperature, hydrograph, groundwater recharge, nutrient cycling, sedimentation, and sediment transport.
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3. Habitat formerly accessible to chinook salmon and still in pristine or near-normal conditions but from which they are presently cut-off, and which can provide additional high-quality habitat and/or further contribute to normal river function if reconnected to the main channel. Such habitat needs to be preserved in order not to foreclose future salmon recovery options. c) Preliminary Delineation of Critical Habitat and Linkages
Estimates of current riparian conditions in the Snohomish River basin summarized in the "Snohomish River Basin Conditions and Issues Report" (Pentec 1998) provide the basis for our preliminary delineation.
Several kinds of key habitat exist in and adjacent to the mainstems of the Snohomish, Skykomish, and Snoqualmie rivers. River frontage that remains undiked, heavily forested, or in wetland condition constitutes ideal target areas for delineation (Pentec 1998). Many of these key areas are listed under multiple critical habitat types because of the gross scale of the Pentec Report and because off-channel habitat and riparian areas may provide rearing habitat and/or process-structuring and maintaining functions. For example, undiked riparian areas currently without back- or side channels may be future sites for channel development, may currently contribute to hyporheic/active channel function, and may contribute large-woody debris to the active channel and off-channel habitat. The same can be said of existing riparian areas and wetland complexes isolated from the river by dikes: they likely contribute hydrologically to channel processes and are potential sites of future off-channel habitat. d) Priority Critical Habitat Currently Accessible to Chinook Salmon
(1) Snohomish River Estuary
• Remaining floodplain delta wetlands.
• Approximately 38 miles of delta sloughs which maintain their connection to the lower Snohomish River and estuary.
(2) Snohomish River Mainstem
• A total of 6.47 miles (both banks combined) along the mainstem lower Snohomish River without dikes and with a riparian corridor of forested vegetation greater than 200 feet wide.
• Two miles of connected off channel floodplain habitat currently providing over wintering habitat.
(3) Skykomish River Mainstem
• Approximately 21.25 miles (both banks combined) along the Skykomish between Gold Bar and Monroe without dikes or rip-rap and possessing riparian corridors of forested vegetation greater than 200 feet wide.
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• The braided reach extending approximately from Gold Bar to downstream of the mouth of the Sultan River (approximately river miles 34 to 41). This is geomorphologically the most complex segment of the Skykomish River below the forks and the most unconstrained segment. It contains key spawning areas for the Snohomish River summer stock and likely contains important rearing habitat for juveniles and over-wintering habitat for stream-rearing juveniles from this stock and probably from the Bridal Veil Creek stock as well.
(4) Skykomish River Forks
• Beckler, Tye, and Foss catchments: spawning habitat for Bridal Veil Creek stock.
• North Fork Skykomish River from confluence to Bear Creek Falls.
(5) Snoqualmie River
• A total of 8.75 miles along the mainstem between Fall City and Duvall without dikes or rip- rap and possessing riparian corridors of forested vegetation greater than 200 feet wide (much of this contains sloughs and wetlands with differing degrees of connection to the main channel which currently provide varying levels of off-channel rearing and over-wintering habitat).
• Comparable habitat between Duvall and the confluence of the Snoqualmie and Skykomish rivers remains to be determined.
• Griffin Creek catchment: in addition to contributing to water quality, the lower reaches likely provide rearing for juveniles and over-wintering habitat for stream-rearing juveniles of the Snohomish River Fall chinook stock.
• Key spawning areas in Tokul Creek, Raging River, Tolt River and the mainstem Snoqualmie River downstream of these tributaries.
(6) Basin-Wide
• Approximately 150 miles of floodplain tributary channels among the three mainstem basins (lower Snohomish, Skykomish, and Snoqualmie rivers) which are both unditched and possess at least moderate amounts of riparian vegetation. The fraction of this total occurring in each basin remains to be determined. e) Critical Habitat For the Preservation of Key Habitat-Forming and Habitat- Maintaining Processes
(1) Snohomish River Estuary
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• 32 acres of remaining estuarine emergent marsh, 37 acres of emergent forested transition zone, and 35 acres of forested riverine tidal zone wetland complexes that remain along the Snohomish River mainstem.
(2) Snohomish River Mainstem
• A total of 6.47 miles (both banks combined) along the mainstem lower Snohomish River without dikes and with a riparian corridor of forested vegetation greater than 200 feet wide.
• A total of 2.86 miles (both banks combined) along the mainstem lower Snohomish River with dikes and with a riparian corridor of forested vegetation greater than 200 feet wide. This includes areas such as Bob Heirman Park (Thomas' Eddy).
(3) Skykomish River Mainstem
• Approximately 21.25 miles (both banks combined) along the Skykomish River between Gold Bar and Monroe without dikes or rip-rap possessing riparian corridors of forested vegetation greater than 200 feet wide.
• The braided reach extending approximately from Gold Bar and the mouth of the Wallace River (approximately river miles 35 to 41).
(4) Skykomish River Forks
• Beckler, Tye, and Foss catchments: critical for maintaining key habitat-forming and maintaining processes related to temperature, hydrograph, woody debris recruitment, and coarse sediment contributions.
• North Fork Skykomish River above index to Bear Creek Falls; South Fork Skykomish River.
• Habitat above Bear Creek Falls.
(5) Snoqualmie River
• A total of 8.75 miles (both banks combined) between Fall City and Duvall without dikes or rip-rap possessing riparian corridors of forested vegetation greater than 200 feet wide.
• Approximately 1 mile (both banks combined) along the mainstem between Fall City and Duvall which is diked but not rip-rapped and approximately 1 mile (both banks combined) which is rip-rapped but not diked, possessing corridors of forested riparian vegetation greater than 200 feet wide.
• Griffin and Tokul creek catchments: the integrity of the entirety of these catchments is necessary to secure their contributions to mainstem water quality and hydrology and to
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preserve existing rearing/refuge habitat conditions and, in the case of Tokul Creek, potential high quality spawning habitat currently unavailable to chinook salmon.
• Upper South Fork Tolt River catchment, Mt. Baker-Snoqualmie National Forest, which plays an important role in maintaining water quality and flows.
• Middle Fork Snoqualmie River catchment, including Pratt River and Taylor River watersheds. Critical component of the hydrograph of the sub-basin; critical contributor to temperature and sediment budget.
(6) Basin-Wide
• Mature upland forests, which contribute to the hydrological functions of the watershed. f) Quality Habitat Currently Inaccessible to Chinook Salmon
(1) Snohomish River Estuary
• 300 acres of tidal sloughs cut off from the estuary and lower mainstem Snohomish River, many of which are unnamed. Among the largest remaining intact sloughs are Swantail Slough, Deadman Slough, and Deadwater Slough. Along the mainstem Battle Slough, Hanson Slough, and Shadow Lake are among the major sloughs cut off by dikes.
(2) Snohomish River Mainstem
• Upper Pilchuck River above the City of Snohomish diversion dam.
(3) Skykomish River Mainstem
• Wallace River above the Wallace River hatchery.
(4) Snoqualmie River
• Tokul Creek upstream of the WDFW hatchery: contains approximately 1/2 mile of high quality chinook spawning habitat.
F. MARINE SURVIVAL
1. Ocean Conditions The ocean’s carrying capacity for anadromous salmonids is dynamic in time and space. Since 1976, a major change has occurred in the northeast Pacific Ocean, creating unfavorable ocean conditions for salmonids in the Coastal Upwelling Domain. Favorable ocean conditions will be required for full recovery of many depressed stocks (Pearcy 1997).
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All stocks of anadromous salmon naturally exhibit highly variable abundance. Much of this variation can be attributed to variable survival and growth rates in the ocean (Pearcy 1997, Hare et al. 1999). Of all the stages in the salmon life cycle, the period of marine residency is the one that is least affected by human activities. Although ocean conditions are not easily controlled, the pattern of salmonid marine survival must be understood so that the other elements of the recovery plan will be resilient to marine survival fluctuations (Lawson 1993).
Marine conditions are cyclic and recent evidence, such as much improved pink and chum marine survival, suggests that conditions may be becoming more favorable for Puget Sound salmon stocks. Regardless, trends in ocean survival remain a great uncertainty for Snohomish River chinook salmon and problematic freshwater conditions are only now being seriously addressed.
The effects of the marine environment on Pacific salmon stocks are covered in detail in other references (e.g. Pearcy 1992, 1997; Hare et al. 1999). There is a concise summary of some of the relevant marine processes in the Puget Sound Salmon Stock Review report (PSSSRG 1997).
Currently, Puget Sound salmon stocks generally appear to be experiencing a period of lower than average marine survival. Unfortunately, due to lack of separate data for freshwater and marine survival rates for chinook salmon, it is impossible to quantify the degree to which marine survival has declined. However, measured marine survival rates (smolt to adult) for Puget Sound coho salmon have ranged between 4% and 30% over the past two decades, with the lower levels observed in some recent years (Tweit, WDFW, memorandum January 28, 1998). Chinook salmon are also likely to exhibit significant variability in ocean survival rates. Recovery plans must take this variability into account so that it is not confused with the impacts of changes in the watershed.
2. Salmon as Prey and Predator Throughout most of their complex life history, salmon are members of a large, complex food web being both predator and prey and interacting with a wide variety of other freshwater, estuarine and marine organisms. These predator-prey relationships have always been a part of the ecology of salmon and have helped shape the evolution of the species, their life history strategies and population characteristics. Marine mammals in particular have taken salmon as their prey (although not exclusively), especially where adult salmon are concentrated during their final return migration. The significance of this factor has become a concern where marine mammals, especially seals and sea lions have taken a proportionately greater number of individuals from a salmon stock in critically low abundance.
In the North Pacific Ocean, approximately fifteen species of marine mammals reportedly eat salmon. Predation on salmon smolts and adults has been documented for beluga whale, harbor porpoise, larga seal, stellar sea lion, California sea lion, Pacific harbor seal and orca (killer whale). Salmon form an appreciable portion of the northern fur seal's diet off the Washington coast (Fiscus 1980). A report to Congress states, "predation by California sea lions and Pacific harbor seals may now constitute an additional factor in salmonid population decline and can affect recovery of depressed salmonid populations in some situations" (NMFS 1999).
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Other fish and avian predators no doubt also feed upon sub-adult salmon during their estuarine and early marine residency. Diving seabirds (family Alcidae) such as puffins and auklets take sub-adult salmon during their intense seasonal breeding period to feed their nestlings, although these likely only constitute a small fraction of their diet (Ralph 1978). Understanding the overall role that marine mammal and other predation may play in marine survival is important for long- term management of salmon stocks in general, and in particular, the Snohomish River chinook.
Another important factor to consider is that with changing ocean conditions, the primary prey species of sub-adult and adult chinook salmon may also have declined in response. Changing ocean conditions, such as have been documented in the Pacific Ocean in recent years, have a cascade effect on overall food web relationships and general oceanic productivity. Local Puget Sound populations of Pacific sand lance and surf smelt may have declined over the last few decades due to ocean and nearshore factors not well understood. Known spawning locations and numbers of Pacific herring in particular, have declined by a significant factor over the past few decades, suggesting that prey availability for salmon may be seasonally and locally limited (Salo and Ralph 1990 unpublished manuscript).
G. NON-NATIVE SPECIES Concern is growing over the environmental impacts of animal and plant species that originate from other areas. The problem is referred to with various terms, including aquatic nuisance species, non-native species, invasive species and non-indigenous species.
The control and eradication of non-native species poses a serious challenge with respect to riparian and wetland habitat restoration efforts. Infestations of noxious weeds, for example, may displace native plants and arrest successional development of local plant communities critical for salmonid habitat and food chain support. Typical intruders include reed canarygrass (Phalaris arundinacea), purple loosestrife (Lythrum salicaria), cordgrass (Spartina alterniflora), Scots broom (Cytisus scoparius), and the ubiquitous Himalayan blackberry (Rubus discolor).
The problem is not limited to plants. Non-native animals impact salmonids and other native species in a variety of ways, including competition for food and habitat and even direct predation.
Atlantic salmon (Salmo salar) have been reported in Puget Sound and its tributary river systems infrequently over the past decade. Although this species was introduced into British Columbia as fertilized eggs in 1905, this introduction is thought to have been unsuccessful (Hart 1973). However, since the establishment of net pen rearing sites in Washington and British Columbia in the 1970s, Atlantic salmon have been seen in the area. They have been reported successfully reproducing in the wild on Vancouver Island (Howard 1998, Province of British Columbia 1999). The source of these fish is thought to be accidental releases from net pen operations. Several such incidents have occurred in Puget Sound in recent years, the most recent being approximately 100,000 Atlantic salmon, weighing up to 9 pounds each, which escaped from pens on the south end of Bainbridge Island on June 13, 1999 (Anderson 1999). Atlantic salmon may detrimentally affect wild Pacific salmon in several ways, including the introduction of disease, competition for spawning or rearing habitat, and predation. To date, instances of interaction between Atlantic salmon and chinook salmon have not been documented.
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Non-native species can be introduced through shipping, aquaculture, importation of exotic plants and animals and other human activities. In Puget Sound, current research into non-indigenous species has focused on tracking and controlling a few species of concern. Most non-indigenous species in Puget Sound, however, are neither recognized nor known. Once recognized, the impacts of an introduced species are difficult to predict. While the impacts of many “non- indigenous species can be unnoticed, others can be catastrophic…. Although they are often more difficult to assess, the ecological effects of non-indigenous species can be more severe than the economic effects.” (Bookheim and Berry 1999).
The implications of non-native species to an ESA-listed species such as chinook salmon and its ecosystem are unknown at this time because of a lack of information. The initial statewide effort has been to establish baseline inventory information in Puget Sound and develop planning and regulatory activities within the context of federal strategy.
To address the paucity of baseline information in Puget Sound, the Washington Department of Natural Resources jointly organized the Puget Sound Expedition with the University of Washington and the San Francisco Estuary Institute. In September 1998, this cooperative project conducted the first systematic survey for marine non-indigenous species in the region, focusing on invertebrate and algae species. Everett was one of 25 sampling sites chosen to represent a range of environmental and anthropogenic conditions in the state’s inland marine waters.
The survey collected and identified 39 non-indigenous invertebrate, algae and vascular plant species in six days of sampling, with much analysis remaining to be completed. Ten of the non- indigenous species collected had not been previously reported in Puget Sound, increasing the number of known non-indigenous species in Puget Sound salt and brackish waters to 52 (Bookheim and Berry, 1999).
H. DATA GAPS The Technical Committee identified important gaps in the available information as it assembled this initial work plan to conserve and recover chinook salmon in the Snohomish River basin. They have not been prioritized or developed into a comprehensive research program for the watershed, but they are listed here to provide a starting point for that effort.
1. Basin-Wide • Assess and update maps of existing flood control facilities to identify opportunities for reconnecting rivers and streams with their floodplains, or otherwise improve the habitat values of such existing facilities.
• Identify and map channel migration zones and evaluate potential for LWD recruitment on a basin-wide scale. Document current abundance and function of in-channel LWD and identify opportunities for accelerated riparian forest recovery.
• Continue redd scour/fill studies to better understand the relative impact of this factor on egg to emergence survival of salmonids. Increase stream gauging locations to better inform recovery planners of the characteristics of tributary hydrology. Analyze hydrology by sub-
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basin under different future development scenarios to determine whether present development planning regulations protect hydrologic processes.
• Develop sediment budgets for all sub-basins. Identify areas that are high in fine sediment content, particularly in the vicinity of major chinook salmon redd concentrations. Identify sources of sediment and prioritize restoration activities. Evaluate riparian conditions in agricultural areas to determine their relationship to increased bank erosion. Identify areas that are particularly susceptible to land disturbances, bank erosion, and slope failures.
• Conduct an updated inventory of floodplain wetlands in the Snohomish River basin with respect to location, size, class, and functions and values. Prioritize the wetlands for acquisition and restoration activities.
• Determine the percent impervious coverage of each of the sub-basins in WRIA 7 to identify sub-basins at risk.
• Gather more detailed knowledge of historic conditions to establish a baseline against which changes could be measured and to identify possible areas for restoration activities.
• Monitor juvenile production in the system to help assess the impact of watershed conditions on the population. This could be estimated by a smolt outmigration study. The ideal smolt trapping effort would include traps in the lower Skykomish, lower Snoqualmie, and lower Snohomish rivers. Comparison of the results from the three traps would allow for the differentiation between the life histories of the summer and the fall stocks.
• Development of an appropriate harvest management plan will require better knowledge of the production function. The appropriate production function relates the biomass of adult fish to the biomass of fertilized eggs deposited in the spawning grounds. This approach will require collection of new information and development of new production models, which may result in new escapement goals, for example, based on the number of females or biomass of eggs rather than the number of fish. Fishery managers need models that accurately predict fish production for given conditions and quantity of habitat.
• Intensive annual sampling of natural spawning populations of chinook salmon in the Snohomish River system is needed to estimate size, age, and sex distribution of natural spawners, hatchery or wild origin of spawners, freshwater life history distribution of spawners, contribution of coded-wire tagged fish to the spawning population, and timing of spawning. Sampling goals are 5-10% or 50-100 adult fish from each naturally spawning chinook salmon stock in the system.
• Determine the feasibility of coded-wire tagging of naturally-produced juvenile chinook salmon from the system. If feasible, then a multiple-year tagging study should be undertaken. One objective of this study should be to separately estimate the fishery exploitation rates on chinook salmon from the Skykomish and Snoqualmie river systems to determine if differential harvest is one cause of the different escapement patterns for these two systems.
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• To be more effective, fishery managers need more information on chinook salmon life history and effects of management. Particularly on spawning fish (accurate number, sex ratio, age, size, contribution of hatchery fish, and geographic distribution), stock composition of fisheries, egg-to-fry survival rates, survival and habitat use of juvenile and adult wild fish, and accurate estimates of outmigrating smolt abundance. In the past, it was assumed that the information collected from hatchery fish was a reasonable surrogate for wild fish. However, growing evidence suggests that information obtained from hatchery fish is often not representative of wild fish and that a program to specifically assess the needs and behaviors of wild fish may be necessary.
• Better determination is needed of chinook salmon ocean survival rates. Chinook salmon are more closely associated with both inshore and near-bottom habitat than other more open ocean and pelagic species (pink, chum, and sockeye salmon) and thus ocean survival rates for these other species may not be good indicators of chinook salmon survival trends.
• Conduct comprehensive ground and aerial surveys of the Snohomish River system to estimate the annual total number of natural spawners for each stock in the system. The assumptions of the survey methods will be evaluated and the methods will be modified accordingly if necessary.
• Quantitative limiting factors analyses conducted on a species-by-species basis are needed, and efforts to that effect have been initiated for chinook salmon in certain sub-basins in the Snohomish River watershed.
• Conduct an inventory of temperature in the mainstem rivers and tributaries to determine baseline conditions during the hottest time of the year. Repeat in subsequent years in areas where riparian vegetation has been replanted or cleared to assess shading effects.
• Better understanding is needed of the competition and predation impacts of hatchery salmon on wild juvenile chinook salmon.
• Determine if the inclusion of naturally spawning hatchery fish as part of the spawning escapement with no accounting for differences in size, age classes, sex ratio, and spawner viability has a significant impact. The contribution of the hatchery fish to the natural spawning population is unknown and needs to be clarified. An ongoing study involving the otolith marking of all the hatchery production from both the State’s Wallace River hatchery and the tribal hatchery on Tulalip Bay will allow the development of information on the contribution of hatchery fish to the natural escapements.
• Based on information collected since 1993 (e.g. Anne Marshall, WDFW, memorandum 1 Aug. 1997), the Snohomish River stock delineation may need to be reviewed. For example, should the fall stock be divided into two stocks (Sultan River and Snoqualmie River), or perhaps some other division? Also, with the fish from above Sunset Falls included as a portion of the brood stock for the hatchery summer chinook salmon program, and the similarity of hatchery and natural fish, it may be that the Bridal Veil Creek stock should be considered a segment of the Snohomish River summer chinook salmon stock.
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• Develop a better understanding of the impact of past and present timber harvest activities on habitat conditions.
• Develop a better understanding of the impact of past and present rural and urban activities on habitat conditions.
• Conduct an analysis/inventory of ski areas, road building, mass wasting, revetments, bank hardening and culverts.
• There is a paucity of data on the existence of non-native species (fish and invertebrates) in the freshwater bodies of the Snohomish River basin and their effects on salmonids. To address the issue of the impacts of non-native species on chinook salmon in the basin, a baseline survey should be conducted to find out which non-native species are present. More research is also needed into the potential effects of Atlantic salmon on native species.
• Conduct a Landsat/digital aerial photography study of sub-basins and cover along streams and within the 100-year floodplain to identify land cover characteristics that affect chinook salmon habitat and watershed processes.
2. Snohomish River Estuary • Gather more data on juvenile salmonid “micro-use” by various stocks in the estuary. Current data, while well summarized, doesn’t paint the whole picture of how juvenile fish are using the available habitat.
• Learn more about the role of large woody debris in estuaries. Few good data sources exist on that topic.
• Determine an appropriate fish window for allowing instream work, given the considerable amount of fish movement from March until July.
• Gather more information on the abundance and distribution of eelgrass and the role it plays in juvenile rearing in the nearshore.
• Gather more information on spawning and rearing of herring, surf smelt and Pacific sand lance in Port Gardner and the lower Snohomish River estuary.
• Document sources and pathways of energy flow in the food web for juvenile salmonids in the lower estuary and in Port Gardner.
• Further study is needed on predation at the river mouth and its influence on salmonid stocks in the basin. Are marine mammal populations at historic levels? Does log rafting attract more sea lions? There is little understanding of the impacts of avian predators or of increasing marine mammal populations on salmonid stocks in the basin.
• Develop a more complete understanding of the nearshore environment, its ability to support out-migrant smolts, and the inter-species factors that exist there.
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• The impact of toxic contaminants in the estuary and nearshore waters and sediments is unclear. Indications from other Puget Sound systems (e.g. Duwamish Waterway) suggest that even brief exposures to a similar suite of contaminants can, at least temporarily, suppress immune function and decrease disease resistance (Arkoosh et al. 1996). Whether these impacts are significant on a population level is difficult to ascertain.
3. Snohomish River Mainstem • In the Snohomish River mainstem and the Pilchuck River, the impacts of elevated stream temperature and exclusion of off-channel habitat on overall productivity of the basin may be the most significant issues. Current surveys to assess juvenile salmon usage and restoration opportunities of mainstem Snohomish River habitat and off-channel rearing areas are needed.
• Conduct an inventory of off-channel habitat.
• Determine the location and distribution of chinook spawning in the Pilchuck River.
4. Skykomish River Mainstem • Determine how egg survival is affected by river channel bed scour.
• Identify, perhaps via snorkeling surveys, what habitat juveniles are using.
• Determine if there are spring chinook salmon in the basin and if so, where.
• Determine if the apparently high number of yearlings is due to the amount of available habitat or the unique characteristics of the stocks.
• Evaluate whether geomorphological analysis can be conducted to help define “potential” habitat that may not currently be used.
• Research the extent to which loss of LWD has reduced the potential habitat.
• Gather historical data and examine how the mainstem Skykomish River channel changed (in area, type, etc.) between the 1930s when the first diking occurred and today.
• Gather data on historical changes in the braided reach channel length and area.
• Study how groundwater recharge affects landslides on the terraces.
• In the Skykomish River system, increased peak-flow frequency and amplitude resulting from forestry and other land-use practices significantly impact fish production by increasing channel scour and instability, and reducing the recruitment and retention of pool-forming large wood. Quantitative studies and modeling are needed to address these impacts within the mainstem Skykomish River and each of its tributaries of historically high salmonid production.
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5. Skykomish River Forks • Gather better hydrological information, especially concerning low flows.
• Determine the role of production above Sunset Falls. Is that production critical to the Bridal Veil Creek fall stock and/or the Snohomish River basin chinook salmon population? How do these fish fit in the recovery effort? How does the anadromous production above Sunset Falls fit with the Wild Salmonid Policy? What are the competition issues between anadromous and resident species?
• More detailed genetic sampling is needed with chinook salmon from the North Fork Skykomish River and above Sunset Falls. This information is needed to better tease out the relationships between the various chinook salmon stocks.
• Chinook salmon use above Bear Creek Falls needs additional research. In examining the type of habitat available above Bear Creek Falls, the other species of fish present, and general location and water temperature profile, it appears that if spring chinook salmon were historically present in the Snohomish River basin then the most likely spawning area would have been that portion of the basin above Bear Creek Falls.
• Gather additional information on the locations of and preferences for spawning habitat use over time.
• Survey mass soil movements on the upper North Fork Skykomish River.
• Examine how the sediment supply from landslides along the Skykomish River forks and on forest lands affected sediment supply and contributed to changes in channel area between Gold Bar and Sultan (start by conducting a landslide inventory). Evaluate the impacts of landslides and land uses on different tributaries.
• Monitor water quality for targeted parameters.
• Compare historic aerials to identify changes in channel geometry in all major alluvial streams. Compare channel changes on North Fork Skykomish River to changes in hydrology and changes in LWD. Attempt to make causal links between channel changes and natural or man-caused actions or processes.
6. Snoqualmie River • Comprehensively inventory and study levees and revetments on the Snoqualmie River.
• Study the land use effects on low flows in lateral tributaries.
• Assess old oxbows for potential reconnection to the Snoqualmie River between Snoqualmie Falls and the valley.
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VI. ACTIONS
A. INTRODUCTION Salmon recovery depends on many factors, including harvest, artificial production, and habitat management. No single factor can individually bring about successful recovery.
The Technical Committee has assembled an initial set of actions that could be undertaken to conserve and recover salmon in the Snohomish River basin. These actions are based on the best scientific information available about chinook salmon in the basin. This initial technical document does not take into account social, economic or other factors beyond the needs of fish. These considerations are important, and they will be addressed as a next step. It is very likely that some of the proposed actions have significant benefits beyond salmon recovery, and that some of them have significant costs as well.
Fishers, loggers, farmers and developers have already made some changes to protect salmon and their habitat. These user groups and the policies and regulations that guide them may have to change even more for recovery to be successful. Furthermore, public policies continue to allow a relatively high rate of population growth and development and do not reverse historic losses of habitat due to human development. All elements of habitat and fish population diversity must be in place to provide what fish need for their long-term survival and harvest. The collection of actions put forward in this chapter are recommended by the Technical Committee for consideration in developing a chinook salmon conservation and recovery plan.
B. HARVEST MANAGEMENT PLAN Pacific salmon populations can persist indefinitely with some level of fishing. All of the Puget Sound chinook salmon populations have been the basis of spiritually, culturally, and economically important fisheries for over ten thousand years. These fisheries have been conducted continually since people colonized Puget Sound and its rivers simultaneously with the salmon when the last glaciers retreated.
When rates of harvest become too great, however, salmon populations can decline or, if overharvest persists, be driven to extinction. The complexities of Pacific salmon harvest management are covered in detail in many references; a good comprehensive summary can be found in chapters 10 and 11 of the recent National Research Council report (National Research Council 1996). The challenge of harvest management is to find the appropriate fishing levels that will provide harvest opportunity without jeopardizing the productivity of each population or stock.
The effects of salmon overharvest can be reversed when harvest management paradigms are changed. Mundy (1997) reviewed three major Pacific salmon fisheries, all of which were acknowledged to have been overharvested over the past century. Two of these (Bristol Bay and Fraser River sockeye) responded positively to harvest management changes, showing increases in both numbers of spawners and harvest levels within the decade after harvest management
67 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions policies were changed. The other (Columbia River chinook) did not respond to harvest management changes and, in fact, showed continued declines. Mundy concludes that other factors, such as differences in freshwater habitat quality, explain the differences in responses among the systems. Thus, poor harvest management can cause declines in salmon populations, which can be reversed if all limiting factors are addressed.
1. Goal and General Principles Harvest management alone will not restore Snohomish River basin chinook salmon stocks. Consistent with the overall goal of this work plan, harvest of chinook salmon will be managed to provide a high probability of allowing all natural stocks in the system to rebuild to levels that will support directed harvest and other benefits. Numerical goals will have to be established once the data is available to support them. The following general principles guide the details of the plan:
• All natural stocks of Snohomish River chinook salmon (see IV.C and WDF et al. 1993) must be individually considered in the harvest management plan. For some purposes, it is appropriate to combine the stocks into a single management unit for assessment of impacts. However, the plan must not impede the ability of any single stock to rebuild, assuming appropriate artificial production and habitat recovery plans are in place.
• Current management objectives (whether based on fixed goals or exploitation rates) can result in skewing spawning populations towards males and younger and smaller females. Therefore, immediate steps should be taken to assess and reduce where necessary the size and age selectivity of fishery related impacts.
• A new harvest management plan should be developed based on better knowledge of the production function, that is, the processes that govern population dynamics.
• All sources of fishery related mortality count equally in assessing the exploitation rate. These include pre-terminal fisheries directed at chinook salmon such as those in Canada and in the ocean off Washington; pre-terminal fisheries with incidental mortality of chinook salmon such as the north Puget Sound sockeye fishery; recreational fisheries directed at chinook salmon such as the Puget Sound winter blackmouth fishery; hook-and-release mortality in selective recreational fisheries; incidental harvest of Snohomish River chinook salmon in terminal fisheries directed at hatchery stocks, etc. All mortality will be assessed in terms of adult equivalent mortality, that is, as the reduction in the number of adult fish (or biomass of eggs in the new model) that would reach the spawning grounds in the absence of fishing.
2. Interim Harvest Management Plan The interim harvest management plan will be in place concurrently with collection of data and modeling to develop a new production function and harvest management plan. The interim plan has several key components:
• Maintain the exploitation rate (includes all sources of fishery-related mortality, see above) on each brood below a maximum level set such that harvest will not impede the ability of the stocks to rebuild;
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• Maintain escapement for each stock above a minimum level to assure the continued viability of each stock;
• Reduce fishery-induced size and age selectivity; and
• Continually monitor and evaluate the results of harvest management and modify the plan as required, based on the information gathered, to meet the goals. a) Maximum Exploitation Rate
The exploitation rate includes all fishery-related mortality (in terms of adult equivalents) in all fisheries affecting Snohomish River chinook salmon. During the rebuilding period this rate should:
1. Be sustainable under current conditions of freshwater and marine survival;
2. Be low enough to have a high (>80%) probability of not impeding the ability of the Snohomish River chinook salmon stocks to rebuild, assuming appropriate habitat protection and restoration actions are implemented; and
3. Not be unduly constrained below the level necessary to achieve 1) and 2) above.
Although the Puget Sound Salmon Management Plan (United States v. Washington, 626 F. Supp. 1405 (1985)) establishes maximum sustainable harvest (MSH) as the normal management objective for primary natural management units, the Technical Committee recognizes that this interim plan for Snohomish River chinook salmon will not necessarily meet this objective. The interim exploitation rates will be below the rates that would result in MSH. Therefore, for the duration of the interim plan, the overall harvest of Snohomish River wild stocks may be less than the maximum sustainable level. Collection and analysis of the appropriate information required to assess the system’s capacity and productivity for chinook salmon and the development of new exploitation and escapement objectives based on biomass of eggs is a necessary prerequisite to developing a long-term harvest plan that will yield MSH.
Under the interim plan the maximum exploitation rate will be based on the best currently available information and updated whenever significant new information becomes available. Initially, the co-managers will use a rate of 35% adult equivalent fishery-related mortality, by brood year, in all fisheries as a maximum rate. Due to size and age selectivity of fisheries and the greatly different fecundity of chinook salmon of different ages, the 35% rate is equivalent to a higher rate (perhaps 40-45%) measured in terms of potential egg biomass. b) Consideration of Each Individual Stock
Even after reducing the exploitation rate on the overall management unit, the potential of some individual stocks to rebuild could still be jeopardized due to harvest. For example, the timing of fishery impacts could result in harvesting one stock at a significantly greater rate than the others,
69 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions or the productivity of one stock could be significantly lower than the others. For the duration of the interim plan, the co-managers will monitor the natural spawning escapement for each stock.
Since the current goal for the entire system was based on the observed average for the 1965-1976 period (Ames and Phinney 1977), the individual stock averages for the same period and the proportional contribution of each stock’s escapement to the total during that period are useful benchmarks for checking the deviation of any one stock’s escapement from the overall pattern for the management unit.
For example, Table 3 reveals that the Snohomish River fall stock has exhibited escapements above its average in 13 of 18 years since 1980, while the Snohomish River summer stock has only exceeded its average in 2 of those 18 years. This indicates a difference in performance of these stocks, which is likely caused by some combination of three factors, as discussed below in the artificial production management plan. c) Reduce Fishery-Induced Size and Age Selectivity
There will be a reduction in size and age selectivity merely as a consequence of the reduction in exploitation rates mandated by the interim harvest management plan. Monitoring of fish sizes and ages in fisheries and spawning populations should allow the co-managers to assess the degree to which this is taking place. In addition, they should evaluate the following management measures, which might further reduce selectivity:
• Mark all hatchery-produced chinook salmon with a visibly identifiable exterior mark and prohibit the retention of unmarked fish in all Washington Oregon, and southern British Columbia recreational fisheries;
• Investigate the effects of minimum size limits in hook-and-line fisheries;
• Implement pulse fishing (for example, harvest only in alternate years) in certain large scale directed chinook salmon fisheries known to be age and size selective (such as the Canadian troll fishery);
• Investigate the effects of year-round fishing for chinook salmon in Puget Sound, especially fisheries targeting immature chinook salmon; and
• Investigate the effects of the use of only large mesh gear in gillnet fisheries directed at wild chinook salmon stocks and consider requiring variable mesh gear when these fisheries become allowable. d) Continual Evaluation of Harvest Management
Annual evaluation of harvest management will have several aspects:
• Assessment of spawning escapement numbers (in terms of natural origin recruits) and age and sex composition for each natural stock in the system.
70 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions
• Assessment of the exploitation rate on each age class in all fisheries.
• Assessment of age or size selectivity in key fisheries impacting Snohomish River chinook salmon.
• Sampling of chinook salmon caught in each terminal fishery (sport and net) for coded-wire tags. The sampling goal is at least 20% of the harvest for net fisheries and at least 10% of the harvest for sport fisheries. Net fishery sampling should be stratified by week and sport fishery sampling should be stratified by month.
• Evaluation of the assumptions underlying the escapement estimation methodology resulting in suggestions for improving the methods.
3. Development of Long-Term Harvest Management Plan The long-term harvest management plan will require a new model that incorporates survival and growth, tracks fish separately by maturation age and sex, and considers the different capacities for production of each stock. The co-managers will immediately begin a program to collect and evaluate information necessary to develop a long-term harvest management plan for Snohomish River chinook salmon. The plan will be based on updated assessments of the productivity and capacity of the system. The kernel of the plan will be production functions for each stock relating recruitment biomass to the biomass of fertilized eggs on the spawning grounds. The long-term harvest management plan will be designed to provide long-term maximum sustainable harvest from the entire management unit under the constraint that the viability and diversity of the production of each stock will not be jeopardized.
Integration of harvest management with habitat and environmental conditions, such as stream flow and water temperature, will require expansion of the model to include freshwater growth and survival.
C. ARTIFICIAL PRODUCTION MANAGEMENT PLAN
1. Background Snohomish River basin chinook salmon are managed primarily for natural production. Artificial production is provided to achieve defined objectives consistent with the principle that the risks to natural production caused by artificial production will be minimized. The hazards of artificial production most likely to present risks to Snohomish River chinook salmon are:
1. Introgression of genes from domesticated hatchery populations into wild populations;
2. Ecological and indirect genetic effects on wild populations from hatchery populations due to competition, predation, and other ecological factors; and
3. The masking of the true status of wild populations if managers incorrectly identify hatchery- produced fish in natural spawning areas as natural-origin recruits.
71 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions
The co-managers will review existing artificial production programs in the Snohomish River system to identify aspects that could be modified to reduce risks to the natural stocks of chinook salmon in the Snohomish River basin. Any newly proposed artificial production projects will be evaluated for risk to wild chinook salmon stocks and will only be approved if it can be demonstrated that the risk will be minimal.
A state-tribal-NMFS work group is developing a procedure for documenting and assessing the potential risks of both existing and proposed artificial production projects. There is currently a draft plan under development, the Artificial Production Workgroup Plan (APWP), which has not yet been completed or reviewed.
Each artificial production program must have an operation plan, which states the objectives along with all information necessary to evaluate the risks to natural chinook salmon stocks. Operating plans for all existing chinook salmon production programs in the Snohomish River basin and Tulalip Bay are available from the Washington Department of Fish and Wildlife and the Tulalip Tribes. Key elements of these plans are repeated below under Program Descriptions.
2. Categories of Artificial Production The APWP provides four categories for artificial production programs, dependent upon both the primary management objective (harvest or wild stock recovery) and the strategy employed (isolated from natural production or integrated with natural production). Each of the categories is fully described in the APWP. Different risks and benefits are associated with each of these categories, and programs belonging to different categories have different guidelines and standards to minimize these risks while achieving the intended benefits. The three categories relevant to the Snohomish River basin are described below. a) Integrated Harvest
Integrated harvest projects are intended to use local brood stock to produce fish for harvest while accepting some artificially produced fish spawning in the wild with an associated natural population. In addition to providing harvest benefits, a successful integrated harvest project should not cause substantial changes in morphological, behavioral, or life history characteristics of the associated natural population. Integrated harvest projects are required to use brood stock from the associated natural population.
The contribution of hatchery fish to the associated natural spawning population should be less than 15%6. The rate of gene flow outside of the associated population should be no more than the natural rate of gene flow from the associated natural population to any other population. Integrated harvest projects should have an associated marking and monitoring program to assure that the contribution of natural origin recruits to the natural spawning can be accurately measured without being masked by hatchery strays. Integrated harvest projects should have associated harvest management plans to assure that the presence of artificially-produced fish in a fishery
6 These numbers are in the current APWP draft and have not received policy review or approval.
72 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions will not cause harvest rates on the associated natural population to be too high. b) Isolated Harvest
Isolated harvest projects are designed and managed to limit the genetic and ecological interactions between wild and hatchery fish. Stocks may be isolated physically by space and time or reproductively by intensive management strategies, such as sterilization, intensive harvests, or trap-and-pass strategies at weirs. In isolated projects, brood stocks do not necessarily need to be genetically similar to wild fish so long as a sufficient degree of isolation is maintained. Even if project fish are genetically isolated, no project will be completely ecologically isolated from other projects or species. Isolated harvest projects must include adequate monitoring and evaluation to determine the degree of isolation and its effect on other populations. Monitoring should be designed so that potentially unwanted effects will be detected and corrected as soon as possible.
There is zero intended contribution of isolated harvest projects to natural spawning populations. It is recognized that some straying of these fish will occur, but the gene flow from hatchery fish to a wild stock should be as low as possible, preferably less than 1%7. Monitoring should focus on assessment of wild stock mortality associated with harvest directed at the artificial production, assessment of the potential for gene flow between the hatchery fish and wild populations, and documentation of ecological interactions between the hatchery fish and wild populations. c) Integrated Recovery
Integrated recovery projects are designed to use hatcheries or other artificial production facilities to “jump-start” depressed wild populations. In these projects, artificially propagated fish are intended to spawn in the wild and become fully integrated into the existing wild population or to re-establish natural spawning populations in areas where they have been extirpated. There are currently no projects of this type directed at chinook salmon in the Snohomish River basin. Based on current information, the natural summer and fall chinook salmon populations in this system are sufficiently robust that this type of project is not necessary or desirable as part of this initial plan. In the future there may be a proposal to restore the spring chinook salmon stock that may have historically been present within the system. If an integrated recovery project is proposed as a component of this restoration the project will have to go through a detailed risk assessment before it is initiated.
3. Program Descriptions a) Wallace River Hatchery
The Wallace River hatchery, located at the confluence of Wallace River and May Creek near the town of Startup, is the only chinook salmon hatchery in the Snohomish River basin. The hatchery was built to increase production of coho and chinook salmon in Puget Sound. The
7 These numbers are in the current APWP draft and have not received policy review or approval.
73 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions hatchery also serves as an interim rearing site for fish destined for other hatchery programs, including marine net pen operations and cooperative rearing programs. The primary goal is to enhance and maintain the Wallace River summer chinook salmon stock, and to maintain the Wallace River coho salmon stock.
Wallace River summer chinook salmon is the only stock now released from this hatchery. Non- native Green River fall chinook salmon (Soos Creek) had been released from the facility up through 1996. However, that program was terminated in 1997. Recent genetic analysis (Busack and Shaklee 1995) indicates that the Wallace River summer chinook salmon have significantly different allele frequencies than the Soos Creek fall chinook salmon, suggesting that the two stocks have not interbred at levels that would disrupt the genetic integrity of the Wallace River chinook salmon.
Wallace River hatchery brood stock originated from the native summer chinook salmon and are considered representative of the ESU. There has been no intentional integration with the wild stock in recent years although stray native summer chinook salmon are likely included in the collected adults. In addition, every year, a portion of the returning adults is passed upstream to spawn in the Wallace River above the hatchery site.
The annual production goal calls for 530,000 yearlings and 1,000,000 zero-age fish released on- station. Of the yearlings, 280,000 are released in April and 250,000 in May (Table 6). The latter group is 100% coded wire tagged. These programs are classified as integrated harvest programs. Following the program guidelines, the co-managers are eliminating the out-of-system Green River brood stock from the hatchery. Even with all production derived from the Snohomish River summer stock, they will continue to carefully monitor the contribution of hatchery- produced fish to natural spawning populations. The 15% guideline for hatchery contribution will apply to the combined spawning populations in the Wallace River, the Skykomish River, and other natural spawning populations of the Snohomish River summer stock. b) Tulalip Hatchery
Although not located within the Snohomish River watershed, the Tulalip tribal hatchery program is covered in this section because of its proximity to the Snohomish River and its placement within the Snohomish River WRIA. The Tulalip hatchery is located near Tulalip Bay, fed by small independent tributaries including Tulalip and Mission creeks. This facility rears and releases three types of chinook salmon: Skagit River spring, Snohomish River summer, and Green River fall chinook salmon. All three programs are considered isolated harvest programs.
The spring program is intended to provide chinook salmon for the Tulalip tribal members in an on-reservation terminal area fishery. The program is designed for limited harvest for ceremonial and subsistence, including First Salmon ceremonies in May and June. These chinook salmon can also be taken in mixed-stock waters and available for recreational fishers. There is no evidence of the historical presence of chinook salmon in Tulalip Creek, Mission Creek, or any other streams flowing into Tulalip Bay. Tulalip Creek has been blocked to anadromous fish by a dam since the early 1920s. The spring chinook salmon program, in its current form, was established by agreement between WDFW and the Tulalip Tribes in 1993. This agreement is reflected in the
74 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions annual Future Brood Document and draft Stillaguamish/Snohomish Equilibrium Brood Document. The program currently releases 40,000 spring chinook salmon yearlings (Table 6). The intent is that fish returning to the Skagit, Stillaguamish and Snohomish rivers will be harvested at a low rate appropriate to natural stocks, while fish returning to Tulalip Bay can be harvested at a rate approaching 100%, as long as the terminal fishery can target on hatchery production. All fish are marked with an adipose fin clip and coded-wire tag.
The summer program, with the use of Wallace River brood stock, is an experimental program to determine the feasibility of raising summer chinook salmon at the Tulalip hatchery. Annual releases call for 200,000 fingerling chinook salmon at 50 fish per pound.
Table 6. Current Snohomish River basin chinook salmon releases. Fingerling Yearling Stock Lineage Program Type Release Site Agency/Sponsor / fry 1,000,000 Wallace River Integrated harvest Skykomish River, from WDFW summer/fall Wallace Hatchery 280,000 Wallace River Integrated harvest Skykomish River, from WDFW summer/fall Wallace Hatchery 250,000 Wallace River Integrated harvest Skykomish River, from WDFW summer/fall Wallace Hatchery 40,000 Skagit springs Isolated harvest Tulalip Bay Tulalip Tribe 200,000 Wallace River Isolated harvest Tulalip Bay Tulalip Tribe summer Experimental 1,500,000 Green River Isolated harvest Tulalip Bay Tulalip Tribe 2,700,000 570,000
The largest program is directed at Green River fall chinook salmon. The annual release goal is 1,500,000 fry at 80 fish per pound. This program is intended to provide harvest opportunity in mixed-stock waters for recreational fishers and to Tulalip tribal members and recreational fishers in terminal area fisheries. This program uses Green River origin fall chinook salmon, obtained from surplus escapement at the Wallace River hatchery. However, fall chinook salmon eggs have not been taken at Wallace River for on-station release since the 1995 brood. Once fall chinook salmon are no longer available at the Wallace River hatchery, they are expected to come from other WDFW facilities where this stock is available. An MOU (August 1997) between WDF and the Tulalip Tribes states that WDFW will continue to provide fall chinook salmon eggs unless the Tulalip hatchery converts to a summer chinook salmon program. Beginning with brood year 1993, fall chinook salmon released at the Tulalip hatchery have been mass-marked with distinctive otolith patterns induced by thermal manipulation of incubating waters. In addition, as part of the summer chinook salmon feasibility evaluation, 50 –100,000 Tulalip fall chinook salmon will be marked with adipose fin clips and coded-wire tags. The terminal area fishery and the natural spawning grounds in the Snohomish River are annually sampled to estimate the contribution of Tulalip hatchery fall chinook salmon to both the fishery and spawning populations.
75 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions
4. Actions The Tulalip and Wallace River chinook salmon hatchery programs will include the following monitoring to promote consistency with the goal of chinook salmon recovery. The programs will be evaluated and modified, if necessary, to maintain minimal impact on wild chinook salmon.
• Continued annual mass marking of all hatchery chinook salmon production from Tulalip and Wallace River hatcheries. Marking may be by means of adipose fin clips, otolith marks, or other means, depending upon which method is most suitable for future harvest management plans and amenable to recovery in terminal fisheries and spawning populations.
• Evaluation of competition and predation effects of hatchery production on Snohomish River wild chinook salmon. This study should look at both chinook and coho salmon yearling hatchery production.
• There is an apparent difference in escapement trends for the Snoqualmie River (largely Snohomish River fall stock) and Skykomish River (largely Snohomish River summer stock) systems. Hypotheses concerning the cause of this difference include: negative effect of hatchery production in the Skykomish River system; difference in harvest rates between the fish from the two stocks; and difference in habitat condition between the two systems. The co-managers will design a research program to test these hypotheses.
• Taking the results of the above into account, the co-managers will evaluate overall production levels, rates of yearling versus fry production, and harvest patterns on hatchery fish to determine what adjustments to the hatchery programs are necessary to assure that the appropriate guidelines are met.
D. HABITAT MANAGEMENT PLAN
1. Principles Underlying Work Plan Habitat management alone cannot restore chinook salmon populations, but it is a necessary component of recovery. Current conditions in the freshwater and estuarine environments (and the policies and practices influencing them) must be modified in order to reestablish the natural conditions and processes that shaped salmon evolution. Successful recovery of chinook salmon is unlikely without these changes. The Technical Committee's recommendations build on the following habitat management concepts and principles:
• Emphasize protection and reconnection of habitat;
• Use historical information to guide today’s decisions;
• Preserve and restore the natural ecosystem processes;
• Use monitoring and assessment to guide adaptive management; and
• Preserve options for the future.
76 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions a) Emphasize Protection and Reconnection of Habitat
The highest priority of this strategy is protection and reconnection of the component parts of the system that are currently functioning well and providing the environmental conditions that allow fish populations to thrive. Protection can involve acquisition of high quality habitat to be managed for preservation of those features. The wilderness areas system on federal lands and the natural resource conservation areas on state lands are two models of habitat protection programs. Other protection strategies include conservation easements or incentives for private landowners to maintain habitat on their land by directing conflicting land uses away from critical areas.
Development and population growth are placing increasing pressure on salmon habitat and natural processes in the Snohomish River basin. As they become more scarce, areas that support natural ecosystem functions become increasingly critical to salmon. Ecosystems are highly complex in nature and humans have had only marginal success, often at great expense, in recreating aquatic ecosystem processes via engineered alternatives. Preservation of remaining habitat is typically far more cost-effective than large-scale habitat restoration projects. In addition to addressing the problem areas discussed below, the Technical Committee recommends that significant resources be directed to the preservation of remaining critical habitat and linkages, including those listed in section V.E.4.
Reconnection includes reestablishing the connection between channels and floodplains, as well as reconnecting channels to provide for migration corridors. The aim is to facilitate natural interaction between habitat types, thus promoting diversity in distribution and life history strategies for populations of salmon. Especially in the lower reaches of rivers, where most development has occurred, reconnection improves the rate of survival for salmon (adults and juveniles) transitioning between salt and fresh water.
Habitat fragmentation occurs when patches of good habitat begin to shrink in size and become isolated from each other. Fragmentation reduces the value of remaining patches of high quality habitat. For salmonids, it is not sufficient to merely preserve spawning grounds, rearing habitat, and adult feeding territory. The conditions that salmonids encounter in the in-between places must also foster their basic life needs. Therefore reconnection of habitat can be as critical to the recovery process as the existence of key habitat areas. b) Use Historical Information to Guide Today’s Decisions
Historic chinook salmon populations in the Snohomish River basin were consistently more abundant than current populations. There also may have been a wider range of life history characteristics, such as a broader range of river entry timing, larger body size, and higher average fecundity. There may also have been a wider range of age classes; some segments of the population may have reached ages up to eight years. In developing a recovery plan, the Technical Committee will research the historical condition of the chinook salmon resource as well as the freshwater habitat conditions. In addition, the Technical Committee will utilize traditional indigenous information (i.e. cultural stories) to assess historical conditions. The goal is not to recreate all historical conditions, which would require a wholesale exodus of people from the basin. Rather, the objective is to determine which of the key historical factors can be
77 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions restored in a manner that will allow recovery of as much as possible of the historical abundance and diversity of chinook salmon production.
Understanding historic conditions of flow, sediment input and the characteristics of the river channel and riparian/floodplain complex provides clues about what to include in a recovery strategy. Only in this way can appropriate end points be defined to judge the ultimate success of recovery efforts. c) Preserve and Restore the Natural Ecosystem Processes
A key underlying approach of this work plan is to focus on watershed, channel and riparian processes necessary for protecting and maintaining a healthy aquatic ecosystem that supports the life history requirements of salmon and trout. The ecosystem provides the framework within which these species interact and fulfill their biological needs (feeding, reproduction, predator avoidance, etc.).
Protection and restoration of salmonid habitat requires that the natural processes responsible for creating and maintaining habitat features continue to operate. In basins where dams or high density development have irreversibly altered the flow regime or other critical system processes, the only option may be to mimic processes at substantial cost and reduced efficacy. Fortunately, conditions in the Snohomish River basin appear to be suitable for the preservation and restoration of these processes at relatively low cost.
Chapter III contains a description of the physical, chemical, and biological processes at work in Pacific Northwest ecosystems that create and maintain the habitat characteristics to which salmonids have adapted. The major processes to consider on the watershed scale include hydrology (important for spawning and rearing), heat energy transfer (stream temperatures that help control biotic production), sediment input and transport (important for spawning and shaping the channel dimensions), nutrient cycling/solute transport (important for food supply), and delivery of large woody debris (important for habitat formation and sediment storage). Each of the critical processes has been altered to some extent in the Snohomish River basin. This work plan identifies steps to restore these watershed processes that provide productive freshwater, estuarine and nearshore habitat for chinook salmon and all salmonids. d) Use Monitoring and Assessment to Guide Adaptive Management
Adaptive management implies a commitment to monitoring and assessment. The recommendations of the Technical Committee reflect current understanding of fish ecology and the best available basin-specific information, but neither of these bodies of knowledge is complete. Ecosystems and their responses to human activities embody a degree of complexity that scientists have only recently begun to understand. This implies a certain amount of unpredictability with respect to the consequences of a given action within a system. Adaptive management (described in detail in section VI.G) provides a framework for actions to be taken and adjusted over time based on new information gathered through monitoring the results of the actions. The Technical Committee strongly recommends that all proponents of recovery actions
78 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions include the steps of adaptive management, (define objectives, monitor to determine outcomes, adjust actions based on results of monitoring) in their proposals. e) Preserve Options for the Future
A recovery strategy should preserve options for the future and avoid actions with irreversible consequences. The chinook salmon population has dropped to dangerously low levels in many watersheds in Puget Sound. Some stocks appear to be more affected than others are. The most recent 12-year escapement average (1987-1998) for the Snohomish River summer stock is 827 fish, 37% below the average from 1965 to 1976 (from Table 3). In this situation, there is a powerful incentive to protect this particular stock from further decline to preserve the remaining genetic stock diversity of chinook salmon in the Snohomish River basin. Actions should be taken to be sure the Snohomish River summer stock does not fall to critical levels.
Land and water management activities should be selected to provide both protection and future flexibility. Some activities, such as cutting riparian forests, foreclose options for many years. It takes decades for a mature coniferous forest to regenerate to the point at which it can provide shade, nutrient delivery, and large woody debris delivery functions. If the riparian zone is converted to agricultural or urban development, full recovery of riparian functions may never occur. Some restoration actions provide greater protection of future options. For example, acquisitions of critical areas preserve future options by maintaining core populations and securing access to conduct restoration activities if necessary.
2. Categories of Action a) Protection
The first criterion of any action undertaken in the context of salmon species listed under the ESA is to avoid doing harm to the species. The Technical Committee recommends evaluating ongoing and proposed activities to determine whether they are likely to impact chinook salmon or other salmonids in the basin. Those activities shown to have negative effects should be abandoned, modified, or mitigated to prevent harm. A variety of actions can contribute to the conservation of critical habitat and the protection of key processes. Acquisitions, regulations and voluntary stewardship activities each have roles to play in halting the loss of habitat and alteration of ecosystem processes. b) Restoration and Remediation
Habitat restoration and remediation are necessary steps of a salmonid recovery plan. The most effective forms of restoration and remediation are efforts designed to restore the processes that create and maintain habitat. Recovery of these processes will require many seemingly small activities, just as today’s habitat problems are the accumulated result of many small activities over the years.
79 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions c) Enforcement
Enforcement of existing and proposed regulations is also essential to protecting salmon and their habitat. Jurisdictions must have the capacity to enforce regulations to prevent further alteration of watershed processes and, consequently, aquatic habitat. d) Research and Monitoring
Another element of the recovery approach is a commitment to resolve uncertainties by investing in research and monitoring. Current gaps in available information may limit the Technical Committee's ability to direct energy in the most effective manner possible. A comprehensive limiting factors analysis has not yet been completed for the Snohomish River basin. There is no comprehensive inventory of habitat conditions. Additional data gaps are listed in section V.H, and filling some of those gaps will be valuable for the development of an effective recovery plan.
Monitoring is an essential component of adaptive management. It provides the means to make judgments as to the success or failure of collective recovery efforts and to make adjustments as warranted. Monitoring will provide the information needed to determine whether the ecosystem is responding to recovery actions in the intended manner, and the ecosystem’s response will dictate the next steps. Consequently, jurisdictions must commit the necessary talent and attention to research and monitoring to be successful in their recovery efforts. e) Education
Education of the public is another tool that leads to protection of salmon and salmon habitat. Education can help people see the consequences of activities such as riparian clearing and floodplain development. It can also empower people to realize that they can be part of the solution, and it can contribute to the development of an environmental stewardship ethic.
3. Time Scale for Expected Results An ecological process-based preservation and restoration approach to salmonid recovery requires a substantial time commitment before results can be fully realized. Many processes express themselves in time periods that range from decades to centuries. Large, channel-altering floods have a statistical probability of occurrence at intervals of twenty years or more. Riparian forests require a minimum of 60 years to develop some characteristics of a mature forest. If recovery efforts are judged after a few years, the true efficacy in terms of stock recovery will not be evident. The Technical Committee recommends evaluating actions according to the time scales appropriate for the particular actions.
4. Known/Suspected Problems This section covers the nine high priority known or suspected problems that the Technical Committee identified for chinook salmon populations in the Snohomish River basin. Most of the phenomena that are identified as problems also occur naturally, such as siltation or scour of redds. The distinction between natural events and impacts caused by humans is often one of
80 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions scale and frequency. Alteration of the landscape to accommodate human use has accelerated the rate at which disturbances occur and the extent of the disturbances. The objective of this section is to identify some of the key activities that have exceeded natural rates and frequencies and to suggest ways to bring them back into a range to which salmonids are adapted.
Many of the problems and recommendations also affect people and local economies, independent of their effects on fish and fish habitat. Many recommendations will benefit the community as a whole, not just fish and those interested in protecting fish. One example is floodplain buyouts. Purchasing flood-prone properties reduces emergency and disaster relief costs, eliminates the anxiety a family experiences when it finds itself in the pathway of a flood, and provides opportunities to restore habitat for fish. In the past, society has tried to control the processes that create and sustain the ecosystem. That effort has had unintended social and ecological consequences and has led to substantial maintenance expenses. Restoring ecosystem functions will result in numerous benefits beyond improved habitat conditions for fish.
This document does not address the issue of mitigation for proposed actions that would further exacerbate existing conditions. Undoubtedly, some parties will request permits for activities that have adverse impacts on fish habitat. The Technical Committee recommends that such activities should only be allowed under extraordinary circumstances, and that appropriate mitigation should be required. An accounting system of when, where, and why such activities are approved needs to be developed so the cumulative consequences of these actions can be considered in the future assessment of overall recovery program effectiveness. The committee would be willing to work with permitting agencies to develop effective mitigation strategies.
5. List of Problems and Actions a) Loss of channel area and complexity due to bank protection and diking of the river and major tributaries, cutting off the channel from its floodplain
(1) Causes
As development of roads and residences have encroached on the river margin within the historic floodplain, the interaction of river flows and channel dimensions in the Snohomish River basin have been systematically altered in an attempt to prevent damage from flooding. Dikes and levees reduce the effective floodplain area, making more land available for human uses. Along many stretches of river, banks are armored with large interlocking angular rock to prevent bank erosion and channel migration. Construction of bulkheads in tidally influenced and nearshore areas results in analogous impacts to estuarine habitat. These actions have substantially eliminated shallow nearshore areas and backwater channels, caused a reduction in gravel recruitment, arrested side channel and gravel bar formation, and reduced riparian vegetation cover and large woody debris recruitment.
81 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions
(2) Link to processes
The most substantial change brought about by modification of the bank structure is the disruption of the natural characteristics of flooding events. Floodplains serve as overflow storage facilities that reduce flooding effects on the main channels. When dikes are constructed to confine the river to a narrow corridor, floodplain areas lose their ability to provide this overflow function in all but the most extreme floods. Floodplain/channel interactions influence channel hydraulics, groundwater hydrology, sediment transport, nutrient cycling, and delivery of large woody debris. Bank protection arrests channel migration and normal channel formation processes and increases local hydraulic sheer stress, causing more downstream bank erosion, bed scour and fill, and loss of low velocity refuge habitat for juvenile and adult fish. Alterations of the channel generally reduce the overall channel area, reducing the amount and diversity of available habitat.
(3) Recommended actions
Protection Prevent any additional modification of undisturbed/natural banks in the basin. Prohibit floodplain land uses that are incompatible with channel meandering and natural flooding, or that create the demand for additional bank and floodplain alterations. Identify and acquire significant stretches of undisturbed river corridor that continue to function unimpaired.
Restoration Enhance riparian features of existing unmodified reaches. Remove or relocate existing levees, dikes, and revetments to restore floodplain/riverine connections. Where removal is impossible and maintenance occurs, retrofit facilities to reduce impacts. Examples of retrofits include levee setbacks and bioengineered bank designs, which incorporate large woody debris, rounded rock, natural fabrics and native plant revegetation of the bank and buffer. Offer incentives to retrofit private facilities that pose a continued threat to river processes. Potential candidates for removal/relocation include the Tolt, Pilchuck, and Raging river levees, diked portions of the Snohomish River downstream of the mouth of the Pilchuck River, the Skykomish River buyout section, and diked portions of the Snoqualmie River that provide opportunities for substantial floodplain reconnection.
Enforcement Where regulations prohibit shoreline alterations, increase compliance, provide adequate enforcement and avoid issuing exemptions. Where they do not, re- evaluate the reasons why greater protective regulations cannot be defined.
Research Assess and update maps of existing flood control facilities, particularly in the Snoqualmie River basin, to identify opportunities for reconnecting rivers and streams with their floodplains, or otherwise improve the habitat values of such existing facilities. Make such evaluations a routine requirement of scheduled periodic maintenance practices.
Education Prepare educational outreach efforts to inform floodplain landowners, regulators, and design professionals of the impacts of bank protection and flood protection
82 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions
projects on the river system and why it is important to maintain connectivity between the floodplain and river channel. Work with farmers to increase use of alternative crops and alternative timing to reduce their reliance on flood protection facilities. b) Dearth of in-channel large woody debris
(1) Causes
The abundance of large woody debris (LWD) in rivers and streams in the Snohomish River basin has decreased substantially in the past century. Wood was and continues to be intentionally removed to improve navigation and boater safety and to prevent log jams from damaging infrastructure such as bridges at road and rail crossings. The process of large woody debris recruitment into streams has been disrupted, preventing the system from recovering from the campaign to remove logs from waterways. The river system recruits logs through various processes including blowdown of trees from within the riparian zone and bank erosion as the channel migrates in reaches flanked by mature stands of forest. Mature riparian forests are rare as a result of systematic logging and clearing for agricultural activities and urban development over the past century. Rivers are less prone to migrate as a result of the construction of levees, dikes, and revetments for flood protection purposes.
(2) Link to Processes
Large woody debris in stream systems historically existed as individual pieces and in complexes ranging from several logs to rafts several miles in length. Removal of large woody debris causes a variety of process-level impacts. When rivers encounter log complexes, the redirection of flow patterns generates differential scouring forces on the streambed and stream banks. Sorting of streambed sediments and the creation of pool-riffle combinations result, providing important habitat units for a variety of aquatic organisms. Logs and root wads also provide cover, thereby helping fish to avoid predators (Beamer and Henderson 1998).
(3) Recommended Actions
Protection Prevent further removal of LWD from stream channels within the basin. Protect remaining riparian zones to provide a future source of large wood to stream channels. Protect remaining mature riparian forests through acquisitions or easements.
Restoration The long-term solution to the lack of LWD in the rivers and streams of the Snohomish River basin is the reestablishment of mature riparian forests and the reconnection of channel and floodplain complexes. In the short-term, it may be necessary to add large wood complexes to the system to provide an interim supply of LWD.
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Enforcement Enforce regulations prohibiting the removal of woody debris from waterways, including salvage logging. Employ standards for timber harvesting and forest land conversions in riparian corridors that insure LWD input to stream systems at natural rates.
Research Identify and map channel migration zones and evaluate potential for LWD recruitment on a basin-wide scale. Document current abundance and function of in-channel LWD and identify opportunities for accelerated riparian forest recovery.
Education Develop educational materials and distribute information on the role of riparian zones and in-channel LWD in the Pacific Northwest riverine ecosystem. c) Flood flows that scour redds at high frequencies
(1) Causes
Increased occurrence of redd scour (movement of streambed sediments surrounding the nest of eggs or alevins) primarily occurs as a result of alterations in basin hydrology and sediment input/routing brought about by land use changes that accelerate sediment and precipitation run- off patterns. Especially in areas where channel dimensions have been changed or banks have been modified (levees, bridge abutments), even moderate flood events can cause increased scour of redds, which reduces the number of eggs that survive to fry stage. Mortality at the egg to fry stage has always been a large component of the many factors that have reduced salmon survival, but its significance is now greater because of the reduced numbers of spawning fish. Research in some chinook salmon spawning tributaries indicates that redd scour is now occurring at greater frequency than expected given the magnitude of flood events (Orsborn and Ralph 1994, Nawa and Frissell 1993). Leveed portions of a river experience more bed mobilization because high flows are confined to a narrow channel, rather than allowed to spread out across a floodplain.
(2) Link to Processes
Constricting river channels by erecting levees along the bank changes the channel dimensions, usually decreasing the width, increasing the depth and increasing the velocity of water. Stream flow events of sufficient size to cause bedload movement occur more frequently and last longer. Changes in land use alter the pattern of run-off following a rain event. Increased impervious surface cover or loss of tree cover reduces retention of run-off, resulting in more frequent redd scour.
(3) Recommended Actions
Protection Prevent floodplain and upland land uses and practices which are incompatible with natural processes, or which modify the rate and magnitude of flood flows. Prevent loss of wetlands, side channels and proliferation of impervious surface in
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the basin. Maintain forest cover and wetland habitat to the greatest extent possible, especially in riparian areas. Acquire floodplain land as open space.
Restoration Remove dikes, levees and revetments and restore river floodplains to reduce shear stress on the streambed and increase beneficial riparian interactions. Encourage the development and retention of mature conifer forest characteristics in the basin, especially in riparian zones and headwater areas. Upgrade detention facilities.
Enforcement Where regulations prohibit shoreline alterations, increase compliance, provide adequate enforcement, and avoid issuing exemptions. Where they do not, re- evaluate the reasons why greater protective regulations cannot be defined.
Research Continue redd scour/fill studies to better understand the relative impact of this factor on egg to emergence survival of salmonids. Increase stream gauging locations to better inform recovery planners of the characteristics of tributary hydrology. Analyze hydrology by sub-basin under different future development scenarios to determine whether present development planning regulations protect hydrologic processes.
Education Educational outreach efforts to local government planners and floodplain landowners should inform them about the scouring impacts of flood flows on fish habitat in river channels. d) Increased sediment input to streams as a result of slope failures
(1) Causes
Slope failures occur naturally, but their frequency, magnitude and spatial distribution can be increased by human alteration of the landscape, including clearing and road building on steep slopes. Roads intercepting surface and groundwater can change runoff patterns and promote landslides.
(2) Link to Processes
Slope failures can contribute sediment many times in excess of normal background levels. An increase in the incidence of slope failures results in a change in the rate of sediment delivery to the stream. Fine sediments have multiple detrimental effects on aquatic organisms (Klein 1997). For example, fine sediments smother salmon eggs and clog the gills of juvenile salmon. Increased turbidity decreases light penetration, which decreases plant biomass, zooplankton and insect populations, resulting in a smaller and less varied food supply for salmon. Coarse sediments can fill the channel (bed aggradation) and displace channel flow conveyance capacity (volume available for water), causing more frequent over-bank flows. Stream channels choked with too much sediment are prone to lose surface flow in the summer months, as the flow is completely contained within the gravel. Bed scour and fill events can reduce egg to emergence survival at redd sites, as discussed previously.
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(3) Recommended Actions
Protection Prevent actions in landslide hazard areas that contribute to mass wasting, e.g. road building, resource extraction and clearing. Do not allow such activities in landslide hazard areas. Acquire landslide hazard areas. Prohibit logging on sensitive slopes. Require slope stability analysis prior to road building or timber harvesting. Employ innovative road designs to accommodate unimpeded transport of debris and passage of high flows, and to reduce sediment inputs.
Restoration Remove and/or rehabilitate roads in areas prone to landslides. Employ innovative techniques to stabilize existing landslides that are clearly not consistent with natural processes. The Raging River and Tokul Creek catchments are candidates for landslide stabilization activities.
Research Develop sediment budgets for all sub-basins. Identify areas that are high in fine sediment content, particularly in the vicinity of major chinook salmon redd concentrations. Identify sources of sediment and prioritize restoration activities. Evaluate riparian conditions in agricultural areas to determine their relationship to increased bank erosion.
Education Conduct workshops for the construction and development industry on best management practices to minimize and mitigate the impacts of road building, resource extraction and clearing on steep slopes. e) Poor quality riparian forests
(1) Causes
Riparian forests have been cleared for timber sales and to create space for other land uses. Agriculture has been the predominant land use in the Snoqualmie, Skykomish and Snohomish river floodplains, replacing lowland forests. Transportation corridors and residential/commercial development have also contributed to the loss of riparian forests.
(2) Link to Processes
Riparian and floodplain areas are the critical interface between terrestrial and aquatic ecosystems, serving to filter, retain, and process materials in transit from uplands to streams. Riparian vegetation plays a major role in providing shade to streams and overhanging cover used by salmonids. Streamside vegetation stabilizes stream banks by providing root mass to maintain bank integrity, by producing hydraulic roughness to slow water velocities, and by promoting bank building through retention of sediments. Riparian vegetation also provides much of the organic litter required to support biotic activity within the streams. These riparian areas also provide much of the large woody debris needed to create physical habitat structure, (develop pool-riffle characteristics, retain streambed gravel and organic litter, provide substrate for aquatic invertebrates) moderate flood disturbances, and provide refugia for organisms during floods. In
86 Initial Snohomish River Basin Chinook Salmon Chapter VI Conservation/Recovery Technical Work Plan Actions addition to the aquatic functions that riparian areas perform, they typically provide habitat and create unique microclimates important to a majority of the wildlife species occupying the watershed (Spence et al. 1996).
(3) Recommended Actions
Protection Prevent further clearing or other alterations of forests along streams. Locate roads, utility corridors and other infrastructure away from streams and rivers. Identify remaining healthy riparian forests and take measures to preserve them (acquire, enroll in conservation easements).
Restoration Restore riparian communities.
Education Educate landowners and decision-makers in the Snohomish River basin about the importance of riparian forests to salmonid habitat and to landowners. f) Loss of wetlands due to draining for land conversion that eliminates habitat and reduces water retention
(1) Causes
Land conversion for agricultural, commercial, and residential uses has eliminated large areas of wetland habitat in the basin.
(2) Link to Processes
Wetlands play a major role in basin groundwater/surface water hydrology, water quality, nutrient cycling and biotic diversity. Wetlands help retain precipitation, often converting surface water to groundwater. Groundwater moves more slowly through the system and tends to augment flows during the dry season. Groundwater is also an important cold water input to offset solar heat contributions in the summer months. Wetlands filter sediment and provide flood storage. Many species of flora and fauna are adapted to wetland conditions and depend upon them for their existence. Loss of wetlands results in loss of those species, which degrades the quality and quantity of habitat and food sources for species in the upland and aquatic communities.
(3) Recommended Actions
Protection Prevent the loss of wetlands. Protect sites from deleterious inputs, such as herbicides. Purchase wetlands.
Restoration Restore wetlands.
Enforcement Adequately enforce wetland protection laws and measures, such as fencing and buffers.
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Research Conduct an updated inventory of floodplain wetlands in the Snohomish River basin with respect to location, size, class, and functions and values. Prioritize the wetlands for acquisition and restoration activities.
Education Organize field trips for landowners and other stakeholders in the Snohomish River basin to visit high quality wetlands. Explain the importance of these wetlands for both salmonid habitat and agriculture (e.g. the storage and groundwater recharge functions of wetlands; when wetlands are lost, there is less surface water detention/retention available for agricultural operations). g) In redd mortality due to siltation or water quality contamination
(1) Causes
Siltation of redds occurs when fine sediments infiltrate into redds, causing the eggs to suffocate or trapping the emergent fry.
(2) Link to Processes
Siltation of redds occurs when excessive amounts of fine sediments enter stream courses after salmon egg nest construction. Locally high levels of fine sediment loads can occur naturally as a result of mass wasting and bank erosion. Human impacts are also responsible for fine sediment inputs, particularly sediments derived from unpaved road surfaces during rainfall or snowmelt events. Common sources of fine sediments include roads, parking lots, cultivated fields, construction sites, and bank erosion due to riparian clearing or upstream flow alteration (e.g. bank armoring).
(3) Recommended Actions
Protection Ensure that clearing and other activities do not contribute sediment to streams. Limit location and extent of road building. Prohibit any new bank armoring. Require best management practices for construction activities and provide adequate enforcement.
Restoration Relocate, de-commission, or rehabilitate roads, especially unpaved forest roads built to outdated specifications. Encourage low till/no till agricultural practices or use of sediment strips. Improve riparian coverage along streams. Reduce the extent of bank armoring in the basin.
Enforcement Enforce clearing and grading regulations.
Research Develop estimates of background levels (both natural and human caused sources, i.e. basin sediment budgets) for all of the major sub-basins within the Snohomish River basin. Make determinations of sources and apportionment of relative contributions. Identify those basins particularly with geological characteristics
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that make them susceptible to land disturbances, bank erosion, and slope failures, and re-examine the effectiveness of protective regulations currently in force. Increase compliance monitoring and enforcement in these areas as a first priority.
Education Conduct workshops for the construction industry, farmers, and regulators on best management practices to control erosion and sedimentation in streams and rivers. The workshops should explain the importance of keeping fine sediments out of water bodies in the Snohomish River basin. h) Urbanization (road construction, commercial and residential construction, additional bank hardening) that further reduces chinook salmon viability in the basin
(1) Causes
Population growth has fueled a building boom in the Puget Sound area. There are finite limits to the amount of development that can take place in a basin without creating substantial impacts to salmonids. Some basins may have already exceeded those limits (e.g. Quilceda Creek, Allen Creek) and show severe habitat degradation. The Snohomish River basin is continuing to undergo rapid development, i.e. conversion of forest and agricultural land to residential and commercial land uses. The Growth Management Act was adopted to direct growth to specified areas, but has not provided a means to sufficiently limit its impact on chinook salmon habitat.
(2) Link to Processes
Urbanization disrupts natural processes. Hydrology is substantially altered as the effective impervious surface area covers 5 - 20% of the landscape (Booth and Jackson 1997, Booth and Reinelt 1993, Klein 1997, Horner and May 1998). Changes in run-off patterns caused by impervious surfaces alter flow characteristics, potentially rendering habitat unsuitable for salmonids. In addition, fine sediment and pesticide inputs increase dramatically. Benthic communities that provide food for juvenile salmon are impacted by deposition of fine sediment in streams and changes in stream flow characteristics. Species that require clean, cool water are replaced by species that are tolerant of high turbidity and other degraded water quality conditions. The shift in the composition of the benthic community affects the availability of preferred prey items for salmonids and other fish and therefore impacts food webs in riverine ecosystems. Impacts from urbanization are difficult to mitigate.
(3) Recommended Actions
Protection Avoid urban development in floodplains and riparian corridors and near wetlands and headwaters. Avoid far-flung urban centers requiring extensive infrastructure through rural areas. Support land uses that result in low density and low percentage impervious surface coverage in rural areas (forestry, farming, open space). Maintain stream corridors to provide safe passage and other functions for adult and juvenile salmonids. Buy development rights where high-density
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developments are vested in basins that are zoned for rural densities. Encourage greater concentration of population in urban areas. Re-examine local governmental public works activities to ensure they are knowledgeable and consistent in the protection of streams during their routine construction and maintenance activities. Ensure developments manage storm water to preserve natural hydrographs.
Restoration Plant more native trees, particularly conifers, in urban areas. Retrofit development projects with onsite storage and high infiltration systems for stormwater runoff.
Enforcement Monitor construction of new projects for compliance with stormwater standards.
Research Develop economical strategies for accomplishing infiltration of stormwater. Determine the percent impervious coverage of each of the sub-basins in WRIA 7 to identify sub-basins at risk. i) Artificial barriers (dams, tide gates, diversions, culverts, pump stations,) prevent juveniles from reaching rearing habitat
(1) Causes
The development of infrastructure for transportation, utilities and flood protection has resulted in the creation of numerous barriers to fish passage. Chinook salmon are primarily affected by blockages on tributaries that serve as rearing habitat.
(2) Link to Processes
These barriers limit the rearing habitat available to juveniles. Some of them also modify flow regimes, water temperature, and sediment transport.
(3) Recommended Actions
Protection Stop alterations of the floodplain and placement of passage barriers. Evaluate juvenile as well as adult fish passage for new projects and use bridges wherever stream crossings are needed.
Restoration Artificial fish passage barriers should be removed or retrofitted to enable juvenile salmonids to reach rearing habitat in the tributaries of the basin. This involves removal of or alterations to undersized or over-steepened culverts, floodgates (e.g. Tuck Creek), tide gates (e.g. French Creek), and pump stations (e.g. Marshland). Examine culvert outfalls to identify blockages and fix them where necessary.
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Research Investigate alternatives to dams, tide gates, diversions, and pump stations that would accomplish the same flood control, water supply or other goals, but would not present barriers to fish passage.
Education Ensure that Federal, State, County and municipal public works departments and their crews understand the connections between their road work and fish access. Provide fish passage training to all agency personnel responsible for culvert design, maintenance, and replacement.
E. MULTI-JURISDICTIONAL PROGRAMMATIC ASSESSMENT Land use and development regulations are two of the most powerful influences governments have over habitat and the natural processes that shape it. Governments also administer day-to- day programs to construct and maintain roads, drainage facilities, flood control projects, and parks. These activities have both immediate and cumulative impacts on watershed functions.
For recovery to take place, current watershed conditions and the policies regulating them must be changed to reestablish the natural conditions that shaped the evolution of salmon. The Technical Committee recommends conducting a comprehensive multi-jurisdictional programmatic assessment. The results should be used to modify regulations and programs to reduce impacts on salmon habitat.
Government programs, policies, and activities should be analyzed to determine whether they are sufficiently protective of salmon and their habitat. Evaluation of regulations, ordinances that govern local land use, operations and maintenance activities by public works or other municipal or county departments, and code enforcement practices (in addition to assessments of discrete projects and activities), would provide a more accurate picture of the impact of governmental actions and programs on fish habitat in the watershed. Some agencies in the basin have already established rigorous review processes (e.g. King County's Biological Review Panel) which have received a favorable response from the National Marine Fisheries Service.
Both King and Snohomish counties have submitted "Early Action Packages" to the National Marine Fisheries Service that highlight the need to review:
• Comprehensive plan policies; • Sensitive areas ordinances (including floodplain development standards and stream buffers); • Clearing and grading restrictions; • Drainage design manuals; • Water use; • Sewage treatment practices; • Roads maintenance standards; and • Park and natural area management.
The high priority known and suspected problems identified by the Technical Committee can be used to help guide the analysis of land use, development, and ongoing programs in the Snohomish River basin (see Appendix B).
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For example, diking and bank hardening that cuts off side channels from the rest of the floodplain limits juvenile rearing habitat. Assessment of this problem needs to take into account not only the direct impacts of existing dikes and rip-rap, but also the extent to which comprehensive plan policies, zoning, and development regulations are contributing to the demand for additional diking and bank hardening in the future.
F. NON-NATIVE SPECIES MANAGEMENT PLAN At this time, the impact of non-native species on chinook salmon is not well understood. The Technical Committee identified competition from introduced species as a problem in the Snohomish River basin, but not a high priority problem. Additional work will be required to determine what management actions, if any, will be required at the watershed level to address the problem. In the meantime, there are existing federal, state and local efforts to track and control non-native species.
Federal legislation has been enacted and in February 1999, President Clinton signed Executive Order No. 13112 to coordinate the federal strategy addressing non-native invasive species. President Clinton’s budget for fiscal year 2000 proposes an increase of more than $28.8 million to combat invasive species and accelerate research on habitat restoration and biologically-based integrated pest management tactics (Solomon et al. 1999).
At the state level, the Puget Sound Expedition took a first step toward providing baseline information on non-indigenous species present in Puget Sound. However, the ecology and potential impacts of most of the species found are still not well understood (Bookheim and Berry, 1999). State legislation and regulations have been proposed to provide needed regulatory authority and funding for various projects by state agencies (Smith 1999).
G. ADAPTIVE MANAGEMENT STRATEGY AND ACTIONS Each generation assumes that the current way in which natural resources are managed is the good and proper one, yet history has consistently shown this assumption to be false (Frissell and Bayles 1996). These authors argue that none of the schemes for managing ecological systems so far has resulted in truly sustainable resource use and ecological integrity. The present state of declining salmon populations would serve in support of this view. Others argue that land and water use policy decisions that have implications for whole ecosystem functions should only go forward with the knowledge that resource management is a continual learning process requiring clear goals, iterative monitoring, evaluation, and redirection.
Adaptive management is an approach that incorporates monitoring and research to allow projects, ecosystem policies and routine activities, including projects designed to produce environmental benefits, to go forward in the face of some uncertainty regarding consequences (Holling 1978). This approach allows actions to be taken, based on consideration of currently available information, and then modified as needed when new information on its consequences becomes available.
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1. Elements of Effective Adaptive Management The key elements of classical adaptive management are:
• An explicit hypothesis concerning the objectives of a conservation or management activity;
• Monitoring or research designed to test the hypothesis; and
• Provisions for changing the activity in response to information or knowledge gained through the monitoring or research.
An important concept underlying a successful application of adaptive management in an extensive natural resource policy or conservation program is that cumulative learning takes place, so that management decisions and projects can become more effective over time with respect to the conservation objectives of the program. The success of such a program depends on:
1. The ability and willingness of responsible parties to change adaptively in response to new understanding or information after an action is initiated, particularly including information or understanding about the effectiveness of conservation measures; and
2. A credible system of accountability with defined timelines, program milestones, and defined authorities and responsibilities.
Its success further hinges on an understanding of the watershed context within which it occurs (e.g. characteristics of the watershed that may pose natural limits to the potential expression of physical habitat characteristics, biotic conditions), and an understanding of the implications of the decision on chinook populations. Also, one must understand how past, present and future watershed disturbance events, both natural and human-induced, may confound interpretation of cause and effect relationships between contemporary actions and persistent conditions within a watershed.
Several other features of adaptive management are important to its successful application:
• Development of a clear assessment of the problem(s), and identification of appropriate measurable objectives for conservation activities that relate directly to the risk, uncertainty, or problem being addressed;
• A description of the probable implications of various decisions on the resources at risk;
• Defining explicit timelines and benchmarks to judge forward progress on task completion, and an accounting system to showcase progress to interested public and resource professionals;
• Selection of indicators of success, failure, or general performance that are practical to use and capable of signaling change at a level needed to meet conservation objectives;
• Define expected timelines with defined milestones to judge progress on implementation and make timely evaluation of information provided by monitoring and assessment work;
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• Clear response triggers, thresholds, or standards for indicators (that account for environmental variability) so that responses can be detected and appropriate changes can be made to management actions, where appropriate;
• A clear assignment of who is responsible for taking corrective action when environmental triggers, thresholds, or standards are exceeded, as demonstrated through monitoring;
• The use of fair, objective, well understood and accepted procedures for monitoring and research projects; and commitments to fund and implement the overall program; and
• Provisions to deal with expected disputes over interpretation of information.
2. Application of Adaptive Management in the Snohomish River Basin Response Adaptive management in the Snohomish River basin will be used in the evaluation of five levels or types of activities:
• Specific projects to restore, rehabilitate, or enhance habitats (Examples include large woody debris projects in streams, culvert replacements to effect fish passage, or restoration of riparian habitat);
• Broader initiatives that may include policy decisions, resource allocations, capital improvement projects, regulatory actions, and programs (Examples include zoning regulations and volunteer programs);
• The collective conservation measures in WRIA 7;
• Tests of significant assumptions that underlie specific conservation approaches but for which substantial uncertainty exists (Examples include validation of standards for action, and relate to the rigor and confidence of problem assessment); and
• Changes in circumstances, information, or conditions that affect either the advisability of conservation measures or the expectation that such measures will be effective in achieving stated objectives (Examples include jurisdictional changes; new understanding of species biology or conservation techniques; the occurrence of catastrophic environmental events such as floods, fires, landslides, or toxic spills; and changes in the status of stocks or habitats of the target species).
The general approach for adaptive management in the Snohomish River basin will be to develop the following elements and criteria:
• Articulate an explicit hypothesis (or set of hypotheses) related to the stated biological objectives regarding the expected outcome of the activities;
• Design a practical but integrated general monitoring framework (including compliance and effectiveness) and/or research plan based on those defined hypotheses;
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• Threshold criteria or standards for triggering additional or changed mitigation;
• Description of actions that could or would be taken in response to measured outcomes that deviate from expected values or standards;
• A procedure for dispute resolution over interpretation of results;
• A process for developing and implementing any additional mitigation to address the problem for which the need is demonstrated and that clearly identifies the responsibilities of the parties involved;
• A system to ensure that these results and their implications are communicated to responsible public officials in a timely and effective manner.
3. Understanding the limits of Adaptive Management Viewed by some as a panacea, adaptive management in practice has often fallen far short of its true potential. It requires broad political support coupled with technical and policy capability to ensure that monitoring and assessment information have integrity, be thoughtfully considered and used to affect needed changes in management actions when appropriate. To date, there are few successful examples. This suggests that adaptive management will be a challenge and will require collaborative and creative approaches that will test the ways in which our geo-political institutions are currently organized. Understanding the components necessary for making such a venture successful is the most important first step. An understanding of what went wrong in past adaptive management ventures might also help us avoid making those same mistakes (Walters 1997, Rogers 1998, Halbert 1993, Bella 1987).
At the project level, one reason that so many adaptive management programs have failed may be because no provision was made to define or limit the nature and magnitude of adjustments to a project or activity that could be required by regulatory authorities. For example, abandonment of a large capital project after it has been constructed might be impractical if it could produce significant economic dislocations and the failure of an organization to fulfill its mission. Different parties may see different sets of options as acceptable or unacceptable. Clarifying the limits and types of such changes early in a project can help to avoid conflict later.
These policy level decisions should inform, but not drive, the interpretation of the scientific information generated by monitoring and assessment activities. While it is the responsibility of the elected officials to make decisions regarding natural resources and land use, these decisions should be based on an understanding of the scientific assumptions and consequences, intended or otherwise. It is imperative that effective discussion occurs between technical resource professionals (representing many disciplines) and those elected and appointed to make policy decisions. The specific organizational framework of the adaptive management program should be developed soon after the initial recovery plan is initiated.
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Initial Snohomish River Basin Chinook Salmon Chapter VII Conservation/Recovery Technical Work Plan Next Steps
VII. NEXT STEPS
This document is part of an initial effort to guide chinook salmon recovery in the short term while a longer-term, more comprehensive planning effort continues. This chapter outlines the next steps for implementing the initial effort for chinook salmon and for launching the longer term, multi-species effort.
A. PRESENT TO FORUM The Snohomish Basin Salmonid Recovery Forum is a group of elected officials and stakeholder representatives drawn from the Snohomish River basin to address salmon recovery and watershed issues. The Technical Committee will present this initial technical work plan to the Forum in fall 1999 as input to the chinook recovery planning effort.
B. INTEGRATE POLICY CONSIDERATIONS INTO PLAN Some of the technical recommendations to protect and restore chinook salmon are likely to have significant policy implications. The Forum has chartered a policy subcommittee known as the Synthesis Committee to identify these policy implications and develop implementation alternatives, in cooperation with the Technical Committee. The Forum will oversee the development of a chinook salmon recovery plan that addresses the technical issues while balancing other social and economic concerns. The process is envisioned as a dialog between the Synthesis Committee and the Technical Committee to identify implementation alternatives and their implications, followed by Forum discussion and recommendations. The Forum is a voluntary coalition, and each participating organization retains the authority to adopt or reject Forum recommendations. The development and evaluation of policy alternatives for the major actions recommended in this initial work plan will continue from fall 1999 through spring 2000, leading to an initial chinook salmon recovery plan.
C. LAUNCH EARLY ACTIONS Instead of waiting until the plan is complete, early actions will be identified which can benefit chinook salmon right away. The Technical Committee will work with the Synthesis Committee, the Forum, and participating organizations to identify and implement these early actions on an ongoing basis until the comprehensive multi-species conservation/recovery plan is adopted.
D. DEVELOP MORE GEOGRAPHIC SPECIFICITY Where needed, the Technical Committee will work to develop more detailed recommendations at the sub-basin or site-specific level. This will include specific information on remaining critical habitats and linkages as well as information on where actions should be taken first to address the high priority problems. This detailed information can be used to prioritize salmon recovery actions across the basin. One result will be a more comprehensive list of habitat areas that are high priority for protection. The list can be used to direct acquisition efforts as funding becomes available. Process: The Technical Committee will review existing processes for identifying high
97 Initial Snohomish River Basin Chinook Salmon Chapter VII Conservation/Recovery Technical Work Plan Next Steps quality habitat areas, including the King County Waterways 2000 program and the City of Everett's Snohomish Estuary Wetland Integration Plan. A process or combination of processes that best addresses the multi-species recovery objectives of the Technical Committee will be adopted or created. A more comprehensive, multi-species list of priority acquisition sites for the Snohomish River basin will be developed by June 2000.
E. DEVELOP RESEARCH PROGRAM The data gaps presented in this document have not been prioritized. The Technical Committee will review the data gaps and identify the most critical research needs. A proposed research program to support salmon recovery in the Snohomish River basin will be developed by the Technical Committee by December 2000.
F. CREATE FRAMEWORK FOR MULTI-SPECIES PLAN The initial chinook salmon recovery plan is being developed to respond to the ESA listing of Puget Sound chinook salmon as threatened. It is likely that other salmonids will be listed in the future. Rather than addressing each species independently, the Forum and its committees are committed to the development of a multi-species salmonid conservation/recovery plan. The chinook plan will serve as a starting point for this more comprehensive effort, which is expected to take two to three years.
The Tri-County Coalition is currently developing a set of guidelines for salmon recovery planning at the WRIA level. The most recent proposal is to do a one-year high level reconnaissance of major issues, followed by a two-year detailed watershed assessment, followed by another two years to develop a detailed plan and implementation agreements. The details about the timeline and content for the multi-species plan are yet to be finalized.
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Abbe, T.B., and D.R. Montgomery. 1996. Large woody debris jams, channel hydraulics and habitat formation in large rivers. Regulated Rivers: Research and Management 12: 201-221.
Ames, J., and D.E. Phinney. 1977. 1977 Puget Sound summer/fall chinook methodology: escapement estimates and goals, run size forecasts, and in-season run size updates. Wash. Dept. of Fish., Tech. Rep. 29. Olympia, WA.
Anderson, R. 1999. Atlantic salmon escape into Sound from pens. Seattle Times, June 15, 1999.
Arkoosh, M.R., E. Casillas, P. Huffman, E. Clemons, J. Evered, J.E. Stein, and U. Varanasi. 1996. Increased susceptibility of juvenile chinook salmon (Oncorhynchus tshawytscha) from a contaminated estuary to the pathogen Vibrio anguillarum. U.S. Dept. of Commerce, NOAA, NMFS, Northwest Fisheries Science Center, Unpublished manuscript.
Barlow, J., K.A. Forney, P.S. Hill, R.L. Brownell Jr., J.V. Carretta, D.P. DeMaster, F. Julian, M.S. Lowry, T. Ragen, and R.R. Reeves. 1997. U. S. Pacific marine mammal stock assessments: 1996. U.S. Dep. of Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-248, 238 p. NTIS No. PB98-137557.
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Initial Snohomish River Basin Chinook Salmon Appendix A Conservation/Recovery Technical Work Plan Contributing Authors and Committee Members
APPENDIX A
CONTRIBUTING AUTHORS AND COMMITTEE MEMBERS
1. Members of the Snohomish Basin Salmonid Recovery Technical Committee • Bob Aldrich, Snohomish County Surface Water Management Division • Kirk Anderson, King County Department of Natural Resources • Keith Binkley, Seattle City Light • Mike Chamblin, Washington State Department of Fish and Wildlife • Barry Gall, U.S. Forest Service – Mount Baker/Snoqualmie • Nick Gayeski, Washington Trout • Will Hall, Snohomish County Surface Water Management Division • Andy Haas, Snohomish County Surface Water Management Division • Steve Hinton, Snohomish County Surface Water Management Division • Jonathan P. Houghton, Pentec Environmental, Inc., representing Port of Everett • John Kerwin, Washington State Conservation Commission • Curt Kraemer, Washington State Department of Fish and Wildlife • Kim Levesque, Snohomish County Conservation District • Gino Lucchetti, King County Department of Natural Resources • Roy Metzgar, City of Everett Public Works • Meg Moorehead, Snohomish County Surface Water Management Division • Libby Halpin Nelson, Tulalip Tribes • Kurt Nelson, Tulalip Tribes • Bob Newman, Washington State Department of Ecology • Michael Purser, Snohomish County Surface Water Management Division • Steve Ralph, U.S. Environmental Protection Agency • Kit Rawson, Tulalip Tribes • Paul Rentner, Stilly-Snohomish Fisheries Enhancement Task Force • Mindy Rowse, National Marine Fisheries Service • Murray Schuh, Snohomish County Public Utilities District • Megan Smith, King County Water and Land Resources Division • Fran Solomon, King County Water and Land Resources Division • Dave Ward, Stilly-Snohomish Fisheries Enhancement Task Force 2. Other Contributing Authors • Jeffrey P. Fisher, Pentec Environmental, Inc. • K. Michael McDowell, Pentec Environmental, Inc. • Sam Wright, Washington Trout
111
Initial Snohomish River Basin Chinook Salmon Appendix B Conservation/Recovery Technical Work Plan Problem Statements
APPENDIX B
PROBLEM STATEMENTS
The Technical Committee identified 34 problem statements that may contribute to the decline of chinook salmon populations in the Snohomish River basin. The first nine problems were identified as the most important, and they are addressed in the main document.
1. Loss of channel area and complexity due to bank protection and diking of the river and major tributaries, cutting off the channel from its floodplain.
2. Dearth of in-channel large woody debris
3. Flood flows that scour redds at high frequencies
4. Increased sediment input to streams as a result of slope failures
5. Poor quality riparian forests
6. Loss of wetlands due to draining for land conversion that eliminates habitat and reduces water retention
7. In redd mortality due to siltation or water quality contamination
8. Urbanization (road construction, commercial and residential construction, additional bank hardening) that further reduces chinook salmon viability in the basin
9. Artificial barriers (dams, tide gates, diversions, culverts, pump stations) that prevent juveniles from reaching rearing habitat
10. Reduced availability and use of spawning gravel in the summer due to low flows
11. Artificial barriers (dams, tide gates, diversions, pump stations, etc.) prevent adults from reaching spawning habitat
12. Artificial barriers (dams, tide gates, diversions, pump stations, etc.) inhibit juvenile migration to the estuary
13. Poor connectivity of habitat leads to high rates of predation/mortality in migrating juveniles and/or adults
14. Shoreline alterations (bulkheads, piers, fill, etc.) in the estuary disrupt key salt water habitat
15. Water quality contamination renders habitat useless to fish
16. Water quality contamination causes fish mortality
113 Initial Snohomish River Basin Chinook Salmon Appendix B Conservation/Recovery Technical Work Plan Problem Statements
17. Water temperature problems reduce summer rearing habitat and delay upstream migration of spawners
18. Gravel mining disrupts substrate transport and deposition patterns, resulting in redd scouring and reduced egg to emergent survival
19. Excessive human activity in riparian areas (camping, fishing, boating) tramples vegetation, contaminates water and disturbs fish behavior
20. Excessive livestock access to riparian areas leads to loss of vegetation, water contamination, disruption of fish behavior, and damage to redds
21. Water withdrawals exacerbate low flow conditions, impacting rearing habitat and access to spawning areas
22. Residential septic system failures cause water quality contamination and excessive nutrient loading
23. Agricultural activities cause water quality contamination and excessive nutrient loading
24. Industrial activities in the Port Gardner area impact chinook salmon recovery through contaminating water quality
25. Past mining operations continue to contaminate water quality
26. Poaching of adults
27. Predation on adults
28. Disease
29. Predation on juveniles
30. Competition from introduced species
31. Low escapement goal
32. Dredging in the estuary to eliminate fine sediment accumulation problem
33. Reduced availability/abundance of food supply for juveniles
34. Adult migration hampered by lack of holding habitat (pools, log jams, etc.)
114 Initial Snohomish River Basin Chinook Salmon Appendix C Conservation/Recovery Technical Work Plan Technical Evaluation of Problem Statements
APPENDIX C
TECHNICAL EVALUATION OF THE NINE HIGHEST PRIORITY PROBLEM STATEMENTS
1. Loss of channel area and complexity due to bank protection and diking of the river and major tributaries, cutting off the channel from its floodplain.
Link to productivity: Impacts rearing habitat quality (Responses: 9 - high, 1- medium, 0 – low) and quantity (Responses: 8 – high, 2 – medium, 0 – low) Scale of issue: Multiple locations (Responses: 9 out of 10) Severity: Extreme (Responses: 9 out of 10) Trend: Downward (Responses: 7 out of 10) 2. Dearth of in-channel large woody debris
Link to productivity: Impacts rearing habitat quality (Responses: 9 - high, 1- medium, 0 – low) and quantity (Responses: 9 - high, 1- medium, 0 – low) Scale of issue: Multiple locations (9 out of 10) Severity: Extreme (9 out of 10) Trend: Downward (7 out of 9) 3. Flood flows that scour redds at high frequencies
Link to productivity: Reduces egg to emergent survival (Responses: 9 - high, 1- medium, 0 – low) Scale of issue: Multiple locations (8 out of 11) Severity: Extreme to moderate (6 – extreme, 5 - moderate) Trend: Downward (10 out of 10) 4. Increased sediment input to streams as a result of slope failures
Link to productivity: Reduces egg to emergent survival (Responses: 9 - high, 1- medium, 0 – low) Scale of issue: Between Multiple Locations and Localized (4 - multiple locations, 6 - localized) Severity: Moderate (1 – extreme, 6 – moderate, 2 - low) Trend: Downward (6 out of 9) 5. Poor quality riparian forests
Link to productivity: Reduces rearing habitat quality (Responses: 5 – high, 5 – medium, 0 – low) Scale of issue: Multiple locations (9 out of 9) Severity: Extreme to moderate (6 – extreme, 3 – moderate, 1 – low) Trend: Downward (8 out of 9)
115 Initial Snohomish River Basin Chinook Salmon Appendix C Conservation/Recovery Technical Work Plan Technical Evaluation of Problem Statements
6. Loss of wetlands due to draining for land conversion that eliminates habitat and reduces water retention
Link to productivity: Reduces habitat quality (Responses: 6 – high, 5 – medium, 0 – low) and quality (Responses: 6 – high, 5 – medium, 1 – low) Scale of issue: Multiple locations (11 out of 11) Severity: Extreme to moderate (6 – extreme, 5 moderate) Trend: Downward (9 out of 10) 7. In redd mortality due to siltation or water quality contamination
Link to productivity: Egg to emergent survival (Responses: 4 – high, 4 – medium, 2 – low) Scale of issue: Multiple locations (7 out of 10) Severity: Moderate (8 out of 10) Trend: Downward (7 out of 9) 8. Urbanization (road construction, commercial and residential construction, additional bank hardening) that further reduces chinook salmon viability in the basin
Link to productivity: Reduces rearing habitat quality (Responses: 5 – high, 5 – medium, 0 – low) and quantity (Responses: 5 – high, 6 – medium, 0 – low) Scale of issue: Multiple locations (10 out of 11) Severity: Extreme to moderate (5 – extreme, 4 – moderate, 1 – low) Trend: Downward (10 out of 10) 9. Artificial barriers (dams, tide gates, diversions, culverts, pump stations) that prevent juveniles from reaching rearing habitat
Link to productivity: Rearing habitat quantity (Responses: 4 – high, 4 – medium, 1 – low) Scale of issue: Multiple locations (7 out of 10) Severity: Moderate to Low (2 – high, 4 – moderate, 4 – low) Trend: Stable (3 – downward, 6 – stable)
116 Initial Snohomish River Basin Chinook Salmon Appendix D Conservation/Recovery Technical Work Plan Marine Mammal Predation on Salmonids
APPENDIX D
MARINE MAMMAL PREDATION ON SALMONIDS
California sea lions are opportunistic predators exploiting a variety of available food sources (Calambokidis and Baird 1994). Food preferences appear to be seasonal and area specific; evident by the large hake consumption by California sea lions in the Everett area which happen to be adjacent to a major hake spawning ground area (NMFS 1997). Predation on salmonids has been typically recorded from surface feeding observations, scarring on fish, and scat samples. Scat samples collected at haulout sites at Everett and Shilshole Bay contained salmonids in 5% and 25% of the samples, respectively (NMFS 1997).
The number of sea lions in the inland waters of Washington has increased. The Everett area has major haulout sites for these animals. Counts at the Everett haulout sites increased from 108 in 1979 to 1,113 sea lions in 1995 (NMFS 1997). For Puget Sound, annual food consumption for California sea lions was estimated to be 830 metric tons between 1986 and 1994 (NMML 1996). Due to increased abundance of sea lions in 1995, a separate estimate of 2,064 metric tons was calculated.
Pacific harbor seals are found year-round in Washington State waters. From 1978 to 1993, counts of the inland Washington harbor seal stock increased at an annual rate of 7.68% (Huber 1995). The minimum population estimated for this stock in 1996 was 15,349 (Barlow et al. 1997). These seals are the most abundant pinniped in Washington, occupying virtually all types of nearshore habitat. There are approximately 319 known haulout sites in Washington State waters (Huber 1995). As many as 300 seals haul-out on log-booms at the mouth of the Snohomish River (NMFS 1997). Pacific harbor seals have also been reported 15 to 20 miles up the Snohomish River.
Studies indicate that salmonids are not the primary prey of Pacific harbor seals in Puget Sound (NMFS 1997). In a harbor seal consumption study within the Strait of Georgia, Olesiuk (1993) observed hake and herring as being the primary prey species. Salmonids were probably underestimated in studies using otoliths to identify prey because harbor seals often do not eat the heads of large fish. Predation on pink, coho and chum salmon in the fall, steelhead trout in the winter, and chinook salmon in the spring has been recorded in Puget Sound (Everitt et al. 1981, NMFS unpubl. data).
The impact Pacific harbor seal predation can have on salmonid stocks was demonstrated in the Puntledge, a watershed on Vancouver Island in British Columbia. Predation rates of up to 46% of the returning adult fall chinook salmon were documented from surface feeding observations in the estuary (Bigg et al. 1990). In the lower Puntledge River, harbor seals were observed foraging on chum salmon fry and coho salmon smolts at night aided by lighted bridges. In 1995, the total consumption was estimated at 3.1 million chum and 138,000 coho (Olesiuk 1996).
117 Initial Snohomish River Basin Chinook Salmon Appendix E Conservation/Recovery Technical Work Plan Early Action Projects Submitted Under 75.46 RCW
APPENDIX E
EARLY ACTION PROJECTS SUBMITTED FOR STATE FUNDING UNDER 75.46 RCW
FEASIBILITY/DESIGN PROJECTS Tier Project Name Project Description Sponsor Location Cost Estimate Limiting Factors Addressed 1 Marshland F&D improved access/habitat qual. SnoCo, Tulalip lower Snohomish $65,000 LR, FB Tribes 1 Forested Marsh Feasibility of acquisition Tulalip Tribes lower Snohomish $6,000 LR Preservation Eval 1 Forested Wetland F&D acquis.,improved access/habitat Tulalip Tribes lower Snohomish $65,000 LR, FB Zone Rest. Eval. qual. 1 Thomas' Eddy/ Lake F&D acquis.,improved access/habitat SnoCo, Tulalip middle $150,000 LSC, FB Beecher Rest. Eval. qual. Tribes Snohomish 1 Snoq. Levee Setback F&D levee setback or removal on King Co. lower Snoqualmie $150,000 LSC lower Tolt or Raging rivers 1 522 Bridge Site Rest. F&D rest. of diked ag. land Tulalip Tribes middle $29,000 LR, LSC Eval. Snohomish 2 Tye/Beckler Conf Restore habitat, protect property Dwight Baker SF Skykomish $110,000 NA 2 Sky Floodplain Restore flow in side channel, clear Dwight Baker Skykomish $270,000 NA channel Abbreviations: LSC - Loss of stream area and complexity, LWD - Dearth of in-channel large woody debris, FF - Flood flows scour redds, SED – Sediment effects, LBZ – Loss of buffer zones, LF - Low instream flows, FB - Fish barriers/restoring access, LR - Loss of rearing
118 Initial Snohomish River Basin Chinook Salmon Appendix E Conservation/Recovery Technical Work Plan Early Action Projects Submitted Under 75.46 RCW
RESTORATION PROJECTS Tier Project Name Project Description Sponsor Location Cost Estimate Limiting Factors Addressed 1 DD6 Restore floodplain to tidal influence; SnoCo Snohomish $1,450,000 FB, LR, LSC FT restore fresh wetland estuary 1 Snoqualmie Off- Reconnect off-channel habitat King Co. lower Raging R., $400,000 FB, LR Channel Reconn. mid Snoqualmie 1 Groenveld Slough Reconnect off-channel habitat Northwest Skykomish $275,000 FB, LR Chinook Recovery 1 Skykomish Side Chnl. Reconnect off-channel habitat SnoCo Skykomish $150,000 LSC, LBZ, LR 1 Riley Slough Remove non-native (bb,rcg) veg., Snohomish Cons. Skykomish $44,500 LBZ FT replace with native tree/shrub Dist. 1 French Cr. Tidegate Improve access/wq to/in French Cr. SnoCo Snohomish trib. $715,000 FB, LR with self-reg. Tidegate 1 Beckler Rd Decommission/storm proof forest USFS SF Skykomish $258,050 SED FT Decommission roads 1 Beckler River Rest. LWD for habitat complexity USFS SF Skykomish $85,000 LWD, LSC 1 Middle Fork Quilceda Improve coho access, plant buffer SnoCo trib to Snohomish $62,500 LBZ, FB, SED Rest. estuary 2 Miller River Rest. LWD for habitat complexity USFS SF Skykomish $100,000 LWD, LSC 2 McDonald/Craft Restrict livestock access to stream Snohomish Cons. trib to Snohomish $11,500 SED Bridges Dist. estuary 2 NF Sky "Stormproof" road USFS NF Sky $114,000 SED 2 Panther Creek Maintain access through upper Panther Kim Pilchuck River $5,000 FB, LR Cr watershed Williams/SnoCo 2 SF Sky Bank Prot. Bank protection USFS SF Skykomish $70,000 LSC 2 Tye R. LWD Bank protection USFS SF Skykomish $50,000 LSC 2 Richardson Cr. Enhance habitat Salem Woods Woods Cr./Sky $30,000 LSC Streamkeepers Abbreviations: LSC - Loss of stream area and complexity, LWD - Dearth of in-channel large woody debris, FF - Flood flows scour redds, SED – Sediment effects, LBZ - Loss of buffer zones, LF - Low instream flows, FB - Fish barriers/restoring access, LR - Loss of rearing
119 Initial Snohomish River Basin Chinook Salmon Appendix E Conservation/Recovery Technical Work Plan Early Action Projects Submitted Under 75.46 RCW
INFORMATION/RESEARCH PROJECTS Tier Project Name Project Description Sponsor Location Cost Estimate Limiting Factors Addressed 1 Snohomish River Monitor,analyze flow, fine seds., scour Tulalip Tribes Snohomish River $34,000 FF, SED Flow, Sed.Intru., Basin Scour 1 Enhanced Hydr. Data Install new precip. and stream gages SnoCo, Tulalip Snohomish River $67,000 FF, LF Coll. Tribes Basin 1 Juvenile Use Inventory Inventory/map off-channel,edge habitat Washington Trout Snoqualmie $17,034 LR used by juvenile ch. floodplain 1 Pilchuck River Map hist./current hab.; ident. Hist. Tulalip Tribes Pilchuck River $100,000 All Chinook abund., assess lim. Factors 1 Puget Sound Historical Research hist. conds. and subsequent Washington Trout Snohomish River $150,000 All Cond. changes Basin 1 Basin-Wide Habitat Research hist. conds. and subsequent Tulalip Tribes Snohomish River $150,000 All Loss changes Basin 1 SEWIP Salmon Update SEWIP to include City of Everett Snohomish $120,000 FB, LR Overlay provisions/planning for salmon estuary recovery 1 Juvenile Use of Juvenile populations and habitat use in Port of Snohomish $450,000 LR Estuary lower estuary Everett/Pentec estuary 2 Decision Protocol Systematic procedure for decision- Washington Trout Snohomish River $19,200 All making which incorporates uncertainty; Basin costs/benefits 2 Snoqualmie Hab. Inventory habitat focusing on off- King Co. Snoqualmie (Falls $40,000 FB Inventory channel to county line) 2 Landuse Variables Link landuse, flow, sediment to USFS Snohomish River $75,000 - All channel, habitat Basin $150,000 2 Hydrosim Simulate flows under future land use to USFS Snohomish River $100,000 - FF, LF predict habitat changes Basin $200,000
120 Initial Snohomish River Basin Chinook Salmon Appendix E Conservation/Recovery Technical Work Plan Early Action Projects Submitted Under 75.46 RCW
INFORMATION/RESEARCH PROJECTS (CONTINUED)
Tier Project Name Project Description Sponsor Location Cost Estimate Limiting Factors Addressed 2 Enumeration of Estimate ocean-type outmigration from Tulalip Tribes Snohomish River $310,000 LR Outmigration Snoq., Sky, Snoh. Basin 2 Watershed Rest. Develop plan to monitor effectiveness USFS Snohomish River $30,000 All Effect. Rating of rest. Projects and aggregate to Basin watershed 2 Baseflow/Floodflow Improve knowledge of limits to USFS Snohomish River $65,000 - LF, FF rear./spawn. Hab. From low baseflow, Basin $125,000 floodflows 2 Rapid Assessment of Develop GIS database to guide project Washington Trout Snoqualmie River $43,000 All Projects development 2 Snoqualmie Scour Monitor scour in spawning areas King Co. mid Snoqualmie $50,000 FF Survey 2 Snoq. Smolt Trapping Trap and estimate juvenile prod. King Co. Snoqualmie $126,000 NA 2 Aerial Photography Map channel form, projects, USFS SF, NF Sky $52,500 LBZ, LSC, FB, and Videography temperature SED, LR 2 Chinook Salmon Develop database of food usage by Washington Trout Snohomish River $45,000 LBZ Fry/Smolt Gut juve. Basin 2 Snoh. Chinook Estimate contribution of hatchery Tulalip Tribes Snohomish River $60,000 NA Straying Eval. chinook to escapement Basin Abbreviations: LSC - Loss of stream area and complexity, LWD - Dearth of in-channel large woody debris, FF - Flood flows scour redds, SED – Sediment effects, LBZ - Loss of buffer zones, LF - Low instream flows, FB - Fish barriers/restoring access, LR - Loss of rearing
121 Initial Snohomish River Basin Chinook Salmon Appendix E Conservation/Recovery Technical Work Plan Early Action Projects Submitted Under 75.46 RCW
PROTECTION/ACQUISITION PROJECTS Tier Project Name Project Description Sponsor Location Cost Estimate Limiting Factors Addressed 1 Snoqualmie Acquire (fee or easement) floodplain King Co. Snoqualmie R. $1,400,000 LSC, LF, LR Floodplain Acquisition w/potential to restore below Falls 1 Woods Cr. Falls Acquire property at risk SSFETF, SnoCo, Woods Cr (Sky $1,800,000 LBZ, SED Pilchuck Aud. trib) Soc. 2 ORV Exclusion Block ORV access to WF Quilceda Snohomish CD, WF Quilceda Cr. $900,000 SED Tulalip Tribes Abbreviations: LSC - Loss of stream area and complexity, LWD - Dearth of in-channel large woody debris, FF - Flood flows scour redds, SED – Sediment effects, LBZ – Loss of buffer zones, LF - Low instream flows, FB - Fish barriers/restoring access, LR - Loss of rearing
122 Initial Snohomish River Basin Chinook Salmon Appendix F Conservation/Recovery Technical Work Plan Glossary
APPENDIX F
GLOSSARY
Adaptive management The process of implementing policy decisions as scientifically driven management experiments that test predictions and assumptions in management plans, and using the resulting information to improve the plans.
Adipose fin clip The artificial removal of the small fin immediately behind the dorsal fin. A method of marking individual fish so that they can be identified in subsequent life history stages.
Age zero fish A fish that is in its first year of life. Also known as sub-yearlings.
Aggradation, aggrade The geologic process by which stream beds, floodplains, and the bottoms of other water bodies are raised in elevation by the deposition and accumulation of material eroded and transported from other areas. It is the opposite of degradation.
Alevin The larval stage of salmonid development that occurs after the egg has hatched, when the juvenile fish lives in the voids in the streambed gravel for a period of time up to several months until its yolk sac is absorbed.
Allozyme One of a set of structurally different but functionally similar enzymes produced by alternative forms of a single gene.
Alluvial Deposited by running water.
Alluvium Sediment or loose material such as clay, silt, sand, gravel, and larger rocks deposited by running water.
Anadromous Species that are hatched in fresh water, mature in salt water, and return to fresh water to reproduce.
Aquatic insects Insects that live their larval stages in water.
Artificial production Fish production that depends on spawning, incubation, hatching, or rearing in an artificial production facility such as a hatchery or rearing pen.
123 Initial Snohomish River Basin Chinook Salmon Appendix F Conservation/Recovery Technical Work Plan Glossary
Atlantic salmon Salmo salar. A species of trout that is not indigenous to the Pacific Northwest. Atlantic salmon found in streams are generally escapees from fish farms where they are grown for human consumption. It is unknown whether they reproduce naturally in this region.
Bank armoring, bank The artificial application of various materials to protect stream hardening banks from erosion. Also, the formation of an erosion-resistant layer of relatively large particles on the surface of a stream bank.
Bar An accumulation of sand, gravel, or other alluvial material formed at any point in a stream channel where a decrease in water velocity induces sediment deposition.
Bedload Sediment moving on or near the streambed and frequently in contact with it.
Bedload transport The movement of sediment on or near the streambed.
Benthic Pertaining to the bottom (of streams).
Benthic invertebrates Bottom-dwelling invertebrates. Typically, bottom-dwelling aquatic insect larvae.
Biodiversity, biological Variety and variability among living organisms and the ecological diversity complexes in which they occur; encompasses different ecosystems, species, and genes.
Bioengineering Combining structural, biological, and ecological concepts to construct living structures for erosion, sediment, or flood control.
Biological oxygen demand The amount of dissolved oxygen required by the decomposition of organic matter.
Biomass The total quantity, at any given time, of living organisms of one or more species per unit of space. Normally expressed in material units, such as living or wet weight, dry weight, nitrogen content, etc.
Blackmouth Juvenile chinook salmon in marine waters.
Braided channel A stream or river that forms an interlacing network of branching and recombining channels separated by islands or channel bars.
Braided reach A section of a braided channel (See braided channel).
Brood stock Those adult salmonids that are destined to be the parents for a particular stock or smaller group of fish.
124 Initial Snohomish River Basin Chinook Salmon Appendix F Conservation/Recovery Technical Work Plan Glossary
Bull trout Salvelinus confluentus. Bull trout are found in the Snohomish River basin in both resident and anadromous forms. Spawning areas are often associated with cold water springs, groundwater infiltration and the coldest streams in a given watershed. They may hybridize with Dolly Varden.
Catchment See Watershed.
Channel migration area The area defined by the historic, changing meanders of a stream.
Channel morphology The form and structure of a stream channel.
Chinook salmon Oncorhynchus tshawytscha. Also known as king salmon or blackmouth salmon. Chinook salmon is distinguished from other salmon by its large size. The species generally spawns in moderate to large streams and main channels. Chinook salmon are classed as “stream-type” which typically spend one or more years in fresh water before migrating to sea, or as “ocean-type” which migrate to sea during the first year of life. Chinook salmon typically live three to six years but may reach eight years of age before spawning.
Chum salmon Oncorhynchus keta. Also known as dog salmon. Chum salmon spawn in streams of various sizes and the fry generally migrate directly to sea after emergence. They return to freshwater to spawn at between two and five years of age. Chum salmon are second only to Chinook salmon in size.
Coded wire tag A small wire etched with a distinct binary code that is implanted (usually in the snout) in juveniles before they migrate to salt water, which allows for the identification of the origin of the fish bearing the tag when retrieved.
Coho salmon Oncorhynchus kisutch. Also known as silver salmon. Coho salmon are distinguished by black spots on their back and the upper lobe of their tail, and the absence of black pigment along the base of their teeth and lower jaw. This species spawns between October and January in low gradient, small and moderate-sized tributaries. Coho salmon generally rear in low gradient, small and moderate-sized tributaries and side channels of mainstem rivers with a large amount of pool habitat. They also use ponds, lakes, and sloughs, especially during the winter. Juveniles spend approximately one year in freshwater before migrating to estuaries (March to May) and out to sea. They return to freshwater to spawn at between two to five years of age, during the months of August to November. The majority of the coho salmon in Puget Sound return to spawn at age three.
125 Initial Snohomish River Basin Chinook Salmon Appendix F Conservation/Recovery Technical Work Plan Glossary
Confluence The point where two stream channels join to form one channel.
Critical habitat Under the Endangered Species Act, a critical habitat is defined as the specific areas within the geographic area occupied by the species of concern in which are found physical and biological features essential to the conservation of the species and that may require special management considerations or protections.
Cutthroat trout Oncorhynchus clarki. Cutthroat trout are generally found in tributaries, side channels, beaver ponds, and slower reaches of mainstem habitat. Cutthroat trout are found in the Snohomish River basin in both resident and anadromous (sea-run) forms.
Deciduous Pertaining to any of a large family of shrubs and trees whose leaves shed annually, such as maples, birches, cottonwoods, and alders.
Degradation, degrade The geologic process by which streambeds and floodplains are lowered in elevation by the hydraulic removal of material. It is the opposite of aggradation.
Deposition The settlement or accumulation of suspended or bed load material out of the water column and onto the stream bed or floodplain. It occurs when the energy of flowing water and channel gradient are unable to transport the sediment further.
Discharge The volume of water flowing in a stream at a given place and within a given period of time, usually expressed as cubic meters per second (m3/sec) or cubic feet per second (cfs).
Dissolved solids, total The sum of the concentrations of the major dissolved ions and dissolved solids compounds, specifically calcium (Ca2+), magnesium (Mg2+), sodium + + - 2- (Na ), potassium (K ), chloride (Cl ), sulphate (SO4 ), bicarbonate - (HCO3 ), silica (SiO2), Nitrogen (N) and Phosphorus (P).
Diversion dam A dam or weir that diverts stream water from its natural channel.
Dolly Varden Salvelinus malma. Dolly Varden are a salmonid found in the Snohomish River basin in resident and anadromous forms. They typically live in small tributaries and tend to prefer colder waters. They may hybridize with bull trout. Anadromous forms may live two to three years in freshwater and up to seven years at sea.
Ecosystem A biological community and the chemical and physical environment with which it interacts.
126 Initial Snohomish River Basin Chinook Salmon Appendix F Conservation/Recovery Technical Work Plan Glossary
Egg to emergent survival Refers to the survival of fish that have passed through the egg and alevin phases of development and have reached the fry phase.
Electrophoresis A technique that allows biologists to statistically estimate the contributions of fish of different origins to mixed populations by analyzing the genetic variations in fish body fluids and muscle tissue. The process utilizes charged molecules (such as enzymes and other proteins) that separate in an electric field.
Endangered Species Act, A 1973 Act of Congress mandating the protection and restoration of ESA endangered and threatened species of fish, wildlife and plants.
Escapement Those fish that have survived all fisheries and natural predation to make up a spawning population.
Escapement goal A predetermined number of salmonids that are not harvested and will be the parent spawners for a wild or hatchery stock of fish.
Estuary A partly enclosed coastal body of water that has free connection to open sea, and within which seawater is measurably diluted by fresh river water.
Eutrophic A condition in which a water body is rich in dissolved nutrients, is photosynthetically productive, and is often deficient in oxygen during warm periods.
Evolutionary significant A population or group of populations of a species that is unit, ESU reproductively isolated from other population units, and represents an important component in the evolutionary legacy of the species.
Federal Energy The federal agency responsible for licensing and regulating non- Regulatory Commission, federal hydroelectric dams. FERC
Fish passage barrier Any structure that impedes the upstream or downstream movement of fish.
Fishery The act, process, or occupation of attempting to catch fish, whether they are retained or released.
Flood flow A high rate and volume of water flow that exceeds channel capacity and results in flooding of floodplain areas.
Flooding The covering or inundation of land with water.
127 Initial Snohomish River Basin Chinook Salmon Appendix F Conservation/Recovery Technical Work Plan Glossary
Floodplain A low, relatively flat area that is periodically flooded by the lateral overflow of a stream or river.
Fluvial Pertaining to streams or rivers.
Freshet A rapid rise in river discharge and level caused by heavy rain or rapidly melting snow.
Fry Young salmonids that have emerged from the gravel and are up to one month of age. The fry phase precedes the parr phase.
Genetic diversity All of the genetic variation within a group. The genetic diversity of a species includes both genetic differences between individuals in a breeding population and genetic differences among different breeding populations.
Geomorphological An analysis that describes the structure and nature of landforms and analysis their probable origins.
Geomorphology A branch of geology that deals with the origin and nature of landforms.
Glide A stream segment having a slow, relatively shallow run of water with little or no surface turbulence.
Gradient The slope or rate of change in vertical elevation per unit of horizontal distance of a river channel bed.
Harvest management The process of setting regulations for the commercial, tribal, and recreational fisheries to reach management goals.
Herring Clupea harengus. Northern herring, a small Atlantic Ocean fish with a closely related sub-species (Clupea harengus pallasi) in the Pacific Ocean. Herring live primarily over deep water and form schools (shoals) of up to millions of fish. Along the Pacific Coast, they move into estuaries, bays and other shallow water to spawn.
Holding area See holding habitat.
Holding habitat Any habitat that fish use for rest between periods of activity. Generally characterized by flow, low water temperatures, pools, eddies, or slow water formed by logs, boulders, log jams, etc.
Hydrograph A graph showing, for a given point on a stream, the discharge, stage, velocity, or other property of water over time.
128 Initial Snohomish River Basin Chinook Salmon Appendix F Conservation/Recovery Technical Work Plan Glossary
Hydrology The study of the properties, distribution, and effects of water on the Earth’s surface, subsurface, and atmosphere.
Hyporheic zone The area under the stream channel and floodplain that contributes to the flow of the stream.
Impervious surface Surfaces such as pavement, compacted gravel, and roofs that prevent or reduce the infiltration of surface water into soils.
In-redd mortality Mortality of eggs or newly hatched fish prior to their emergence from gravel stream substrates.
Interstitial spaces The voids between streambed gravel, rocks and boulders.
Log rafting The practice of transporting or storing large numbers of logs by floating and towing them in rivers and sloughs.
Large woody debris Large logs (generally twelve inches diameter or larger) and root wads that fell in or near a stream and became part of the riparian and aquatic habitat. Also known as large organic debris.
Macroinvertebrates Invertebrate animals large enough to be seen with the naked eye (e.g. most aquatic insects, snails, and amphipods).
Mainstem The principal stream or channel for any drainage basin.
Mass wasting Landslide processes, including debris falls, debris slides, debris avalanches, debris flows, debris torrents, rockfalls, rockslides, slumps and earthflows, and the small scale slumping, collapse and raveling of road cuts and fills.
Meander An individual bend or curve in a stream channel created by the process of meandering.
Meandering The natural tendency of a stream to curve and move laterally across the land surface.
Mitigation Activities taken to offset the impairment of natural resources.
Mixed stock 1. A stock whose individuals originated from commingled native and non-native parents, or a previously native stock that has undergone substantial genetic alteration. 2. A mixture of salmon of different origins in marine waters.
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Maximum sustainable The maximum number of fish of a management unit that can be harvest, MSH harvested on a sustained basis, measured as the number of fish that would enter fresh water to spawn in the absence of fishing after accounting for natural mortality.
Maximum sustainable The largest number or weight of fish of a stock that can be taken by yield, MSY fishing without reducing the stock biomass from year to year.
Mountain whitefish Prosopium williamsoni. Mountain whitefish are a resident salmonid species. They prefer cold mountain streams, resting in deep pools and feeding in riffle areas. Whitefish have a slender body, short and somewhat pointed head, small mouth and no teeth. Their color is grayish light blue on back, silvery on the side and dull white on the belly. Spawning occurs during October and early November each year and eggs hatch in march. They are active feeders on aquatic insects and fish eggs when available.
Native stock An indigenous stock of fish that has not been substantially affected by genetic interactions with non-native stock or by other factors and is still present in all or part of its original range.
National Marine Fisheries The federal agency responsible for administering the Endangered Service, NMFS Species Act for marine mammals and marine and anadromous fish.
Natural production Fish production that is sustained by natural spawning and rearing in natural habitat.
Net pen A fish rearing enclosure used in lakes and marine areas.
Ocean-type See chinook salmon.
Off-channel habitat Any relatively calm portion of a stream outside of the main flow such as a side channel, slough, dead-end channel, or wetland.
Off-channel rearing area Any off-channel habitat used by salmonids during their freshwater growth phase before they migrate to sea.
Otolith Ear stone. A calcareous concretion in the inner ear of lower vertebrate species. Otoliths can be used to determine age and growth rate in some species.
Over-wintering habitat Freshwater habitat favored by salmonids for winter rearing. Generally characterized by flows that are not extreme, quiet waters, sloughs, side channels, ponds, eddies etc.
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Oxbow A looping river bend or meander cut off from the main flow by a new channel. A crescent-shaped lake formed by the detachment of a river bend from the main channel.
Pacific sand lance Ammodytidae hexapterus. Pacific sand lance are a prey species for salmonids. Spawning generally takes place in estuaries and bays from November to March in shallow waters with sandy substrates. Juveniles tend to school in intertidal zones and just offshore of coastlines until adult burrowing behavior is developed.
Parr Young trout or salmon actively feeding in freshwater. Usually refers to young anadromous salmonids before they migrate to the sea. See smolt.
Pelagic Pertaining to the open ocean.
Pink salmon Oncorhynchus gorbuscha. Also known as humpback salmon. Pink salmon are distinguished from other salmon by their two-year life span and a characteristic hump on large spawning males. They are typically the smallest of the Pacific salmon as adults.
Pool A relatively deep, calm section of a stream.
Rainbow trout Oncorhynchus mykiss. Rainbow trout are the resident form of steelhead trout, spending their entire lives in fresh water.
Reach Any specified section of a stream’s length.
Rearing habitat, rearing Habitat favored by juvenile salmonids for growth and development area before migrating to sea. Generally characterized by shady pools and quiet water, ponds and sloughs.
Redd Fish nests made in gravel (particularly by salmonids) consisting of a depression that is created and then covered after eggs are laid.
Redd scour The removal of the gravel that forms a redd by high water flows. Redd scour typically results in the removal and destruction of eggs buried in the redd.
Resident species Those salmonid species that spend their entire lives in freshwater.
Riffle A stream segment having a broken or choppy surface (white water), moderate or swift current, and shallow depth often broken by the presence of rocks and boulders.
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Riparian Pertaining to anything connected with or adjacent to a stream or other water body. A transition zone between aquatic habitat and upland areas that has a direct effect on the stream.
Rip-rap Large rocks, broken concrete or other structure used to stabilize stream banks and other slopes.
River Mile, RM The distance in miles from the mouth of a river.
Riverine Pertaining to river or stream systems.
Root wad The exposed root system of an uprooted or washed-out tree.
Run The sum of stocks of a single salmonid species that migrate to a particular region, river, or stream of origin at a particular season.
Salmon and Steelhead A cooperative program of the Washington Department of Fish and Stock Inventory, SASSI Wildlife and Washington Treaty Indian Tribes to inventory and rate the status of salmon and steelhead trout stocks on a recurring basis.
Salmonid Any fish of the taxonomic family Salmonidae, including salmon, trout, char, whitefish and grayling.
Sampling The act of taking samples of substances or organisms (fish, water, soil, etc) in the field for later testing and evaluation.
Scour The removal of material by the erosive action of moving water.
Side channel A channel aside from but connected to the main channel and running roughly parallel to the main channel. Characterized by lower flows than the main channel. See slough and off-channel.
Siltation The deposition of fine suspended materials, usually as a result of a reduction of water velocity.
Skykomish River forks The North Fork and the South Fork of the Skykomish River upstream of their confluence near Index.
Skykomish River The segment of the Skykomish River downstream of the confluence mainstem of the North Fork and the South Fork near Index, and upstream of the confluence of the Skykomish River and the Snoqualmie River west of Monroe.
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Slough 1) Low, swampy ground or an overflow channel where water flows sluggishly for considerable distances; 2) A side channel; 3) A section of abandoned stream channel containing water all or most of the year, but with flow only at high water; 4) A creek or sluggish body of water in a bottom-land, floodplain or estuary.
Smolt A juvenile salmonid that is migrating seaward. A young anadromous trout, salmon, or char undergoing physiological changes that will allow it to change from life in freshwater to life in the sea. The smolt state follows the parr state. See parr.
Snohomish River estuary The Snohomish River and its associated side channels and sloughs downstream of the upstream end of Ebey Slough. For some purposes, the estuary is considered to extend as far upstream as French Creek.
Snohomish River The segment of the Snohomish River downstream of the confluence mainstem of the Skykomish River and the Snoqualmie River west of Monroe, and upstream of Ebey Slough, west of Snohomish.
Snoqualmie River The entirety of the Snoqualmie River upstream of the confluence of the Skykomish River and the Snoqualmie River west of Monroe.
Snorkeling survey A method of visually surveying fish presence.
Sockeye salmon Oncorhynchus nerka. Also known as red salmon. Generally a lake- rearing salmon that may spend one to three years in fresh water before migrating to sea. They may spend one to four years at sea before returning to fresh water to spawn. Non-anadromous populations that live and reproduce in fresh water without a period of sea life are known as kokanee.
Spawning The act of laying and fertilizing eggs. Generally, the act of redd (nest) building, laying and fertilizing eggs, and burying the eggs.
Spawner escapement See escapement.
Spawners See escapement.
Spawning grounds, Specific stream reaches where spawning occurs. spawning area
Spawning habitat Habitat favored by salmonids for spawning. Generally characterized by clean gravel and a low percentage of fine sediment.
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Springbrook A stream that derives its flow from groundwater, with relatively constant flow and temperature. Also, the spring or groundwater source itself.
Steelhead trout Oncorhynchus mykiss. Steelhead trout generally live two or more years in freshwater before migrating to sea. They tend to prefer riffle habitat, mainstem areas, and faster water than other species for rearing. Both anadromous and resident steelhead trout are present in the Snohomish River basin. See rainbow trout.
Stock A group of fish that is genetically self-sustaining and isolated geographically or temporally during reproduction. Generally, a local population of fish. More specifically, a local population – especially that of salmon, steelhead trout (rainbow trout), or other anadromous fish – that originates from specific watersheds as juveniles and generally returns to its birth streams to spawn as adults.
Stream-type See chinook salmon.
Sub-basin Same as Sub-Watershed.
Substrate The mineral and organic material that forms the bed of a stream.
Sub-watershed One of the smaller watersheds that combine to form a larger watershed.
Surf smelt Hypomesus pretiosus. Surf smelt are an abundant schooling forage fish that live up to five years and are prey for salmonids. They live in the marine environment and have a maximum length of six inches. Spawning occurs for individual stocks from May through March and occurs at specific beaches where course sand and gravel can be found.
Suspended solids Mineral and organic material suspended, but not dissolved, by the energy of moving water.
Targeted fishery A harvest strategy designed to catch a specific group of fish.
Terminal fishing area A fishing area where a salmonid stock or run has separated from other stocks or runs.
Tributary A stream feeding, joining, or flowing into a larger stream.
Tri-county coalition A coalition of local governments and community leaders in Pierce, King and Snohomish Counties with the goal of responding to the ESA listing of Puget Sound chinook salmon as a threatened species.
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Turbidity Relative water clarity, measured by the extent which light passing through water is reduced by suspended and dissolved materials.
Washington Department The state agency responsible for co-managing fisheries in of Fish and Wildlife, Washington State in cooperation with treaty tribes. WDFW
Washington Department The state agency that was responsible for managing fisheries, now of Fisheries, WDF part of WDFW.
Watershed The total land area that drains to any single river or stream. Also known as a basin or catchment.
Weir A device placed across a stream to divert fish into a trap, to raise the water level, or to divert its flow. Also, a notch or depression in a dam or other water barrier through which the flow of water is measured or regulated.
Wild salmonid policy A salmonid management policy of the State Department of Fish and Wildlife developed with the goal of ensuring that department actions and programs are consistent with the goals of rebuilding wild stock populations to levels that permit commercial and recreational fishing opportunities.
Water Resource A land management unit defined by the boundaries of watersheds. Inventory Area, WRIA
Water Resource The Snohomish River Watershed, including the Skykomish and Inventory Area 7 Snoqualmie river basins.
Yearling A fish that has lived more than one year and is in its second year of life.
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